The correct option is B What the lady said
A noun clause is a dependent clause that functions as a noun. It usually
begins with what, whatever, whom, that and other such relative
pronouns. A noun clause can act as a subject, object, predicate
nominative or object of a preposition, in a sentence.
Option B is
correct as it is a noun clause that functions as the subject of the verb "put". The noun clause has a subject "lady"
and a verb "said".
Option A is incorrect because it is not a noun clause, it is a phrase.
Option C is incorrect because it is an adverb clause of reason that does not function as a subject.
Option D is incorrect because the answer lies in B.