Choose the sentence with an adjective clause-A. He lost more than he…

The correct answer is Option (3) → B

An adjective is a word that describes a noun or a pronoun, for example a tall tree, the food is tasty.

Adjective clause:

• An adjective clause describes a noun or pronoun, as an adjective does.
• It usually begins with a relative pronoun (who, which, that, whose, whom) or a relative adverb (where, when) and comes right after the noun it describes.
• Clauses beginning with than, as far as, as if tell us about a verb or an adjective. They are adverb clauses.

A. He lost more than he could afford. — Incorrect.

• "than he could afford" is an adverb clause of comparison.

B. A man who has industrious habits is sure to succeed. — Correct.

• "who has industrious habits" describes the noun "man", so it is an adjective clause.

C. He advanced as far as he dared. — Incorrect.

• "as far as he dared" tells how far he advanced: an adverb clause.

D. He speaks as if he knew everything. — Incorrect.

• "as if he knew everything" tells how he speaks: an adverb clause of manner.

Contrast: who has industrious habits describes a noun (adjective clause). As far as he dared tells about the verb (adverb clause).