What is the main benefit of using a flexible coupling to join shafts?

Using a flexible coupling to join shafts primarily allows for slight misalignment of the two shafts. This characteristic is essential in applications where perfect alignment is difficult to achieve due to manufacturing tolerances, thermal expansion, or movement. Flexible couplings can accommodate variations in alignment, which helps prevent undue stress on the connected shafts and associated components.

This flexibility in alignment capabilities contributes significantly to the longevity of the machinery and reduces the risk of damaging or misaligning the equipment. Such couplings can also absorb shock and decrease the risk of failure in the system caused by misalignments.

While other benefits like reducing vibrations, improving torque transmission, and minimizing backlash may occur as well, the core advantage of a flexible coupling is its ability to compensate for misalignment, making option B the most accurate choice.