Which of the following is true about the motors used in FTC competitions?

In FTC competitions, the regulations specify that only FTC-legal motors may be used. These motors are pre-approved by the organization to ensure fairness and uniformity in the competition. This means they meet specific performance standards and safety requirements, which helps create a level playing field among all teams. The use of standardized motors prevents teams from gaining an unfair advantage through the use of specialty motors or systems that could introduce significant differences in performance.

On the other hand, the other options imply the use of various types of motors, whether unrestricted, custom-built, or hand-made, which do not align with the regulations set for the competition. The focus on FTC-legal motors ensures adherence to the competition's integrity and fosters an environment where strategy, design, and programming skills are the main determinants of success.