You will be given a definition of a task first, then some input of the task.
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).

Context: Caulerpa is a genus of seaweeds in the family Caulerpaceae (among the green algae). They are unusual because they consist of only one cell with many nuclei, making them among the biggest single cells in the world. A species in the Mediterranean can have a stolon more than 3 metres (9 ft) long, with up to 200 fronds., Margaretia is a frondose organism known from the middle Cambrian Burgess shale . Its fronds reached about 10 cm in length and are peppered with a range of length - parallel oval holes . Its original interpretation as a green alga is not secure ; it also resembles some alcyonarian corals , but a thorough redescription will be necessary to securely classify it . A relationship with the modern green alga Caulerpa is the most up - to - date consideration ., In biology, stolons (from Latin stol "branch"), also known as runners, are horizontal connections between organisms. They may be part of the organism, or of its skeleton; typically, animal stolons are external skeletons., Seaweed refers to several species of macroscopic, multicellular, marine algae., A frond is a large, divided leaf. In both common usage and botanical nomenclature, the leaves of ferns are referred to as fronds and some botanists restrict the term to this group. Other botanists allow the term frond to also apply to the large leaves of cycads and palms (Arecaceae). "Frond" is commonly used to identify a large, compound leaf, but if the term is used botanically to refer to the leaves of ferns, it may be applied to smaller and undivided leaves., In taxonomy, the Caulerpaceae are a family of green algae, specifically of the Bryopsidales., Subject: margaretia, Relation: taxon_rank, Options: (A) branch (B) family (C) genus (D) group (E) species
Output:
genus