Final answer:
In the given sentence, the appropriate punctuation marks to use are a comma (,) or a semicolon (;). Option A and B are both correct.
Step-by-step explanation:
In the given sentence, 'Some people work best in the mornings, others do better in the evenings.'
The appropriate punctuation marks to use are a comma (,) or a semicolon (;).
Option A: Some people work best in the mornings, others do better in the evenings.
Option B: Some people work best in the mornings; others do better in the evenings.
Both options A and B are correct, as they effectively separate the two independent clauses in the sentence.
Option C, which uses a colon (:) instead of a comma or semicolon, is incorrect punctuation in this context.
Learn more about Punctuation in English sentences