Answer: A) Noun clause.
Explanation: A noun clause is a dependent clause that acts as a noun. They can begin with words such as how, that, what, whatever, when, where, whether, which, whichever, who, whoever, whom, whomever, and why. They can act as subjects, direct objects, indirect objects, predicate nominatives, or objects of a preposition. In the given sentence, the bolded words are an example of a noun clause that is acting as the direct object of the sentence.