Our coach will be happy if we arrive by 8 a. m.

the bolded words are what kind of clause?
(if we arrive by 8 a. m.)

adjective clause

adverb clause

noun clause

Adverb clause.

Explanation:

The phrase in the given statement in brackets exemplifies an adverb clause as it is acting as a modifier to the principal clause. An adverb clause is the group of words functioning as an adverb(modifier) in the sentence and describes the condition in which the action is performed or will be performed. Similar to this sentence, as here "if we arrive by 8 a.m." (adverb clause)beginning with the subordinating conjunction "if", describes that "Our coach will be happy". Thus, the second option best complements the purpose of the clause.

mailman is the most possessive answee