The three types of shaft-to-adjacent-shaft power transmission are __________.

The correct choice identifies the three common types of shaft-to-adjacent-shaft power transmission methods: belt drive, chain drive, and gear drive.

Belt drives use flexible belts to transfer power between shafts over a distance. They are typically used for applications requiring speed variation and can absorb shock loads. This method is often found in applications like conveyor systems and various industrial machinery.

Chain drives operate similarly to belt drives but use chains and sprockets. They are more suited for applications requiring higher power transmission without slipping, as chains provide a more positive drive than belts. This is common in bicycles and certain types of heavy machinery.

Gear drives transmit power through gears, providing a mechanical advantage and contributing to speed reduction or torque increase. They are directly connected and can handle high loads and precise motion. Gear drives are essential components in various machinery, including automotive systems and industrial equipment.

The other options contain combinations of methods that don't fully encompass the commonly recognized methods for shaft power transmission in a practical sense, especially when all three methods mentioned in the correct answer are standard in various industrial settings.