Correct option is D
A jockey pulley (also known as an idler pulley) is used in belt drive systems to increase the wrapping angle of the belt around the driving and driven pulleys. Increasing the wrapping angle enhances friction and power transmission efficiency, reducing the risk of belt slippage.
Jockey pulleys are often used in long belt drives where the belt tends to become loose or in situations where the available wrap angle is insufficient for effective power transmission. They help redirect the belt path, ensuring better grip and force transmission between pulleys.
