Answer:
A. Radio waves are electromagnetic but sound waves are mechanical because the radio waves could travel without a medium but the sound waves could not.
Step-by-step explanation:
Electromagnetic waves are waves that do not require a medium for traveling. Therefore, they can travel in a vacuum as well. For example, the sunlight travels from the Sun to the Earth in a vacuum.
Mechanical waves are those waves that require a material medium to travel. Therefore, they can not travel in a vacuum. For example, sound waves can not travel in space.
Therefore, the correct option is:
A. Radio waves are electromagnetic but sound waves are mechanical because the radio waves could travel without a medium but the sound waves could not.