Final answer:
Although I am between paychecks is an example of a phrase because it does not contain a subject and verb and does not express a complete thought. Therefore, the correct option is (3).
Step-by-step explanation:
A phrase is a group of words that does not contain a subject and verb and does not express a complete thought. It is used to add additional information to a sentence.
Option 3) Although I am between paychecks is an example of a phrase because it does not contain a subject and verb and does not express a complete thought. It adds additional information to the sentence.
Examples of complete sentences in the given options are:
1) I went back to school - This is a complete sentence as it contains the subject 'I' and the verb 'went'.
4) I made you a promise - This is a complete sentence as it contains the subject 'I' and the verb 'made'.
Therefore, the correct option is (3).