Yes, that is true. But please make sure the question is stated clearly.
The italicized noun clause is "what i like best about the farm."
Answer: B) Subject complement.
Explanation: A noun clause is a dependent clause that acts as a noun. Noun clauses begin with words such as how, that, what, whatever, etc. Noun clauses can act as subjects, subject complements, direct objects, indirect objects, predicate nominatives, or objects of a preposition. In the given sentence the noun clause is used as a subject complement because it is placed after a linking verb (to be) and it characterizes (or gives further information) about the subject (The fresh air).
The difference between East Egg and West Egg is that East Egg is largely populated by those from "old money," while West Egg is populated by those with "new money." Tom and Daisy Buchanan are from old money because their families have been wealthy for generations.