Answer:
A) Complete sentence.
Step-by-step explanation:
The given group of words is a complete sentence because it has a subject (Carrie) and a predicate (has decided to not use her credit cards; therefore, she will not be buying much) that makes a complete thought. The use of a semicolon between the two independent clauses shows that they are related, and the word "therefore" indicates a cause-and-effect relationship between them.