In this task, you are given a context, a subject, a relation, and many options. Based on the context, from the options select the object entity that has the given relation with the subject. Answer with text (not indexes).
Q: Context: Stationary steam engines are fixed steam engines used for pumping or driving mills and factories, and for power generation. They are distinct from locomotive engines used on railways, traction engines for heavy steam haulage on roads, steam cars (and other motor vehicles), agricultural engines used for ploughing or threshing, marine engines, and the steam turbines used as the mechanism of power generation for most nuclear power plants., Motive Power is a bi-monthly railway related magazine that focuses on diesel locomotives in Australia. The first issue was published on 23 August 1998. Its headquarters is in Sydney. The content includes photographs of locomotives & trains, news about newly delivered and repainted locomotives, technical articles, and fleet listings of the various Australian railway operators. Articles about railway photography itself are sometimes included, as well as articles and advertisements about railway modelling., Rail transport is a means of conveyance of passengers and goods on wheeled vehicles running on rails, also known as tracks. It is also commonly referred to as train transport. In contrast to road transport, where vehicles run on a prepared flat surface, rail vehicles (rolling stock) are directionally guided by the tracks on which they run. Tracks usually consist of steel rails, installed on ties (sleepers) and ballast, on which the rolling stock, usually fitted with metal wheels, moves. Other variations are also possible, such as slab track, where the rails are fastened to a concrete foundation resting on a prepared subsurface., Motive power depot , usually abbreviated to MPD , or railway depot is a term given to places where usually locomotives are housed when not being used , and also repaired and maintained . They were originally known as `` running sheds '' , `` engine sheds '' , or , for short , just sheds . Facilities are provided for refuelling and replenishing water , lubricating oil and grease and , for steam engines , disposal of the ash . There are often workshops for day to day repairs and maintenance , although locomotive building and major overhauls are usually carried out in the locomotive works . MPDs in Britain are now often known as traction maintenance depots ., Steam is water in the gas phase, which is formed when water boils. Steam is invisible; however, "steam" often refers to wet steam, the visible mist or aerosol of water droplets formed as this water vapour condenses. At lower pressures, such as in the upper atmosphere or at the top of high mountains, water boils at a lower temperature than the nominal at standard pressure. If heated further it becomes superheated steam., A vehicle (from ) is a mobile machine that transports people or cargo. Typical vehicles include wagons, bicycles, motor vehicles (motorcycles, cars, trucks, buses), railed vehicles (trains, trams), watercraft (ships, boats), aircraft and spacecraft., A train is a form of rail transport consisting of a series of vehicles that usually runs along a rail track to transport cargo or passengers. Motive power is provided by a separate locomotive or individual motors in self-propelled multiple units. Although historically steam propulsion dominated, the most common modern forms are diesel and electric locomotives, the latter supplied by overhead wires or additional rails. Other energy sources include horses, engine or water-driven rope or wire winch, gravity, pneumatics, batteries, and gas turbines. Train tracks usually consist of two running rails, sometimes supplemented by additional rails such as electric conducting rails and rack rails, with a limited number of monorails and maglev guideways in the mix. The word 'train' comes from the Old French "trahiner", from the Latin "trahere" 'pull, draw'., A locomotive or engine is a rail transport vehicle that provides the motive power for a train. The word originates from the Latin "loco"  "from a place", ablative of "locus", "place" + Medieval Latin "motivus", "causing motion", and is a shortened form of the term "locomotive engine", first used in the early 19th century to distinguish between mobile and stationary steam engines., A shed is typically a simple, single-storey roofed structure in a back garden or on an allotment that is used for storage, hobbies, or as a workshop. Sheds vary considerably in the complexity of their construction and their size, from small open-sided tin-roofed structures to large wood-framed sheds with shingled roofs, windows, and electrical outlets. Sheds used on farms or in industry can be large structures. The main types of shed construction are metal sheathing over a metal frame, plastic sheathing and frame, all-wood construction (the roof may be asphalt shingled or sheathed in tin), and vinyl-sided sheds built over a wooden frame., Subject: motive power depot, Relation: subclass_of, Options: (A) concrete (B) construction (C) content (D) driving (E) energy (F) engine (G) fleet (H) foundation (I) gas (J) locomotive (K) machine (L) magazine (M) nuclear power (N) people (O) power (P) pressure (Q) rail (R) rolling stock (S) running (T) series (U) steel (V) stock (W) temperature (X) top (Y) track (Z) train ([) transport (\) vehicle (]) water (^) watercraft (_) word
A:
construction