Do you know when the last bus leaves?
which kind of clause are the words in bold?
a.
adverb clause
b.
noun clause
c.
adjective clause

The correct answer is option B.

Explanation:

"When the last bus leaves" is a NOUN CLAUSE since its function is direct object in the sentence provided.

Noun clauses perform the syntactic function of a noun. That is to say, they can be subject, direct object, indirect object, subject complement, and object of the preposition.

as much wood as a woodchuck could chuck if a woodchuck could chuck wood.

sadly it cannot chuck wood

i cannot see any of the options