Final answer:
The abductor pollicis brevis muscle is responsible for forming the bulk of the web space on the anterior surface of the hand, and is one of the thenar muscles,the correct option is A).
Step-by-step explanation:
The muscle that forms the bulk of the web space on the anterior surface of the hand is the abductor pollicis brevis. This muscle is one of the thenar muscles located on the lateral part of the palm.
It works in conjunction with the opponens pollicis, flexor pollicis brevis, and the adductor pollicis to form the thenar eminence, which is the rounded contour of the base of the thumb.
The abductor pollicis brevis is responsible for the abduction of the thumb, which is an essential movement in activities requiring manual dexterity, such as typing or writing. The correct answer to the question is b) Abductor pollicis brevis.