Answer:
Adverb clause; called
Step-by-step explanation:
An adverb clause is a group of related words that have at least a subject and a verb, and whose function is to act as an adverb, that is to say, to modify or add detail to adjectives, verbs or other adverbs. This type of clauses often answers why, how, when, where or in what circumstances something is done.
In the sentence, then, the adverb clause is "when there were four minutes left in the first half" because it adds further detail to the main action (the verb): "called." Furthermore, it also answers the question When did Coach Lopez call a time-out? Answer: When there were four minutes left in the first half.