Question: Which of the following sentences uses the correct conjunction?

Options:

1. I will study hard, so I can pass the exam.
2. She is not only a teacher, but also she is a writer.
3. He likes to play soccer, and to swim.
4. They went to the beach, or it was raining.

Correct Answer: I will study hard, so I can pass the exam.

Solution:

\'So\' correctly indicates the purpose of studying hard.