What is the primary purpose of a block and tackle system?

A block and tackle system is designed primarily to provide mechanical advantage when lifting heavy loads, which is precisely why the answer is C. This system consists of multiple pulleys and ropes, allowing a user to lift a heavy object with less force than would normally be required. By distributing the weight of the load across several ropes, the mechanical advantage allows the user to exert less effort while still achieving the desired lifting effect.

The interaction of the pulleys with the rope effectively reduces the amount of input force needed, enabling lifting of heavy objects that might otherwise be impossible to lift directly. This is a critical feature that demonstrates the efficiency of simple machines in everyday applications, particularly in construction and rigging.

Understanding the role of mechanical advantage in a block and tackle system helps clarify its practical applications. It is widely used in various industries where heavy lifting is necessary, showcasing how simple machines can significantly enhance human capabilities.