Final answer:
The sentence that uses the semicolon correctly is option A: 'Documenting the experiment was monotonous; all I did was enter data.'
Step-by-step explanation:
The sentence that uses the semicolon correctly is option A: 'Documenting the experiment was monotonous; all I did was enter data.' A semicolon is used to join two independent clauses without a coordinating conjunction. In this sentence, 'Documenting the experiment was monotonous' and 'all I did was enter data' are both independent clauses. The semicolon provides a clear and concise separation between the two ideas.
Learn more about Semicolon Usage