What is a planetary gear set, and where is it commonly used?

What is a planetary gear set, and where is it commonly used?

• A. A gear arrangement with sun, planet, and ring gears used in automatic transmissions for multiple ratios.
• B. A chain-driven set used in motorcycles for single speed.
• C. A simple spur gear set used in robotics.
• D. A hydraulic pump arrangement used in power steering.

Answer: (A)