Answer:
A
Explanation:
A compound sentence is essentially two simple sentences linked by a conjunction. A simple sentence is made up of a subject and a predicate/verb. Conjunctions make up the acronym FANBOYS, which stands for for, and, nor, but, or, yet, and so.
Look at choice A. Immediately, we see the word "but", so we can think that this is potentially a compound sentence. The first part of the sentence says "The artist uses oil paints now". Here, the subject is "the artist" and the predicate/verb is "uses". This is a simple sentence.
The second part of the sentence is "he used to use watercolors exclusively early in his career". The subject is "he" and the predicate/verb is "used to use". This is another simple sentence.
Thus, since A meets all the requirements for a compound sentence, we know that it is the answer.
