Answer:
If the independent clause is what is being asked for, then it's 1. mike eats a sandwich.
If the dependent clause is what you're asking for, then it's 2. going to the sandwich shop.
Explanation:
An independent clause is a group of words that contains a subject and verb and expresses a complete thought.
A dependent clause is a group of words that contains a subject and verb but does not express a complete thought.
