Answer:
A- brain + cranial nerves (I'm assuming since they are related)
B- Radial nerve
Explanation:
The cranial nerves are pairs of nerves that connect your brain to different parts of your head, neck, and trunk. There are 12 of them, each named for their function or structure. Their uses are mainly categorized as Sensory and Motor. Sensory nerves are involved with your senses, such as smell, hearing, and touch. Motor nerves control the movement and function of muscles or glands.
The radial nerve controls movement of the triceps muscle, which is located at the back of the upper arm and is responsible for extending the wrist and fingers. It also controls sensation in part of the hand.