Which of these is not a compound sentence?

A. Jacob is a very sweet child most of the time, but he occasionally has temper tantrums.

B. She knew how to use most of the programs, but she was unfamiliar with Photoshop.

C. Curtis did not know that he wrote a bad check.

D. none of these

C

Explanation:

There is only one subject and predicate.

C

Explanation:

Compound sentences are two sentences that are combined but could also stand alone,

Ex. Jacob is a very sweet child most of the time. But he occasionally has temper tantrums.

She knew how to use most of the programs. But she was unfamiliar with Photoshop.

This does not apply to C

line a --> main

line b --> young

line c --> atitude