Question

Identify the italicized clause as a noun clause, an adjective clause, or an adverb clause. The instructor decided that this girl must have inherited her father's musical ability.

Answer 1

If the italicized clause is this girl must have inherited her father's musical ability, then this clause is a noun clause.
Since adjective clauses describe the subject, and adverb clauses are basically just adverbs, these two cannot be correct answers.