Select the correct and entire main clause of the sentence.
have you seen my textbook, rafael?
the main clause is

The correct answer is: Have you seen my text book?

The correct main clause of the sentence is Have you seen my text book?

This sentence is a complete one. It is understood as it is. The sentence is clear. It has a subject and predicated. There is no need for other words or expressions in order to understand it. A main clause can form a full sentence or a complete sentence by itself. If a coma appears in the sentence, it is still a main clause.

your answer would be: d) eye contact