Option 1: A microphone does not convert electrical signals to sound waves. It actually does the opposite - it converts sound waves into electrical signals. Therefore, option 1 is incorrect.

Option 2: This is the correct answer. A microphone converts sound waves into electrical signals. When you speak or make any other sound near the microphone, it picks up the sound waves and converts them into electrical signals that can be transmitted or recorded.

Option 3: A microphone does not convert microwaves to sound waves. Microwaves are a form of electromagnetic radiation and are not directly converted by a microphone. Hence, option 3 is incorrect.

Option 4: A microphone does not convert sound waves to microwaves. Microwaves and sound waves are different forms of energy, and a microphone is not capable of converting sound waves into microwaves. Therefore, option 4 is incorrect.

In conclusion, the correct answer is option 2, as a microphone converts sound waves into electrical signals.