TASK DEFINITION: In this task, you are given a question and a context passage. You have to answer the question based on the given passage.
PROBLEM: What was Charles V nationality?, Context: Martin Luther (/ˈluːθər/ or /ˈluːðər/; German: [ˈmaɐ̯tiːn ˈlʊtɐ] ( listen); 10 November 1483 – 18 February 1546) was a German professor of theology, composer, priest, former monk and a seminal figure in the Protestant Reformation. Luther came to reject several teachings and practices of the Late Medieval Catholic Church. He strongly disputed the claim that freedom from God's punishment for sin could be purchased with money. He proposed an academic discussion of the power and usefulness of indulgences in his Ninety-Five Theses of 1517. His refusal to retract all of his writings at the demand of Pope Leo X in 1520 and the Holy Roman Emperor Charles V at the Diet of Worms in 1521 resulted in his excommunication by the Pope and condemnation as an outlaw by the Emperor.

SOLUTION: Roman

PROBLEM: What is sometimes combined with an RPG tube to keep from harming the user?, Context: Rocket-propelled grenades can be—and often are—used against hovering helicopters (e.g., by Somali militiamen during the Battle of Mogadishu (1993)). Firing an RPG at steep angles poses a danger to the user, because the backblast from firing reflects off the ground. In Somalia, militia members sometimes welded a steel plate in the exhaust end of an RPG's tube to deflect pressure away from the shooter when shooting up at US helicopters. RPGs are used in this role only when more effective weapons are not available.

SOLUTION: a steel plate in the exhaust end

PROBLEM: Who was not the first person to write down the idea regarding variable resistance in a telephone?, Context: The question of priority for the variable resistance feature of the telephone was raised by the examiner before he approved Bell's patent application. He told Bell that his claim for the variable resistance feature was also described in Gray's caveat. Bell pointed to a variable resistance device in Bell's previous application in which Bell described a cup of mercury, not water. Bell had filed the mercury application at the patent office a year earlier on February 25, 1875, long before Elisha Gray described the water device. In addition, Gray abandoned his caveat, and because he did not contest Bell's priority, the examiner approved Bell's patent on March 3, 1876. Gray had reinvented the variable resistance telephone, but Bell was the first to write down the idea and the first to test it in a telephone.

SOLUTION:
Gray