Answer:
A). Subject.
Explanation:
Noun clause is described as the cluster or group of words that together function as a noun in the sentence. These clause can function differently as a subject, direct object, predicate nominative, object of a verb or preposition, etc.
In the given sentence, the noun clause i.e. 'What my mother always said to me' is functioning as a 'subject' in the sentence as it acts upon the verb('made sense'). Thus, option A is the correct answer.
