The best statement would be number 3. Sound waves move perpendicular to the medium particles.
Answer:
c. 4 meters/second
Explanation:
The formula to calculate average speed is:

50/200×100%=25% is answer the formula is usefull energy output divided by total energy provided into 100%
All it does is lets him pull in a more convenient direction to raise the load. It has no effect on the required force.