Final answer:
The person receiving a fast ball should be positioned in a forward stance, facing the observer, with upper limbs extended out and lower limbs wide apart.
Step-by-step explanation:
The person receiving a fast ball should be positioned in a forward stance.
In a forward stance, the person is standing facing the observer, with upper limbs extended out at a ninety-degree angle from the torso and lower limbs in a wide stance with feet pointing laterally.
This position allows the person to react quickly and effectively to the fast ball.