TIMID

The correct answer is D. Shy.

Timid is an adjective that means “showing nervousness or shyness.” It is often used to describe people who are afraid of new situations or people. Shy is also an adjective that means “having or showing nervousness or shyness.” However, it is more commonly used to describe people who are reserved or quiet in social situations.

Fast is an adjective that means “moving or happening quickly.” Slow is an adjective that means “moving or happening at a low speed.” Medium is an adjective that means “of a middle or average size, amount, or degree.”

None of these words accurately describes the meaning of timid.