Final answer:
The oculomotor nerve, or Cranial Nerve III, regulates the muscles that control the aperture of the pupil and the shape of the lens. The correct answer is option B.
Step-by-step explanation:
The cranial nerve that controls the muscles responsible for regulating the aperture of the pupil and the shape of the lens is the Cranial Nerve III (3), also known as the oculomotor nerve. This nerve controls all the other extraocular muscles in addition to the muscles responsible for pupil constriction and lens shape adjustment, which are part of the parasympathetic nervous system. The correct answer to the question is therefore B) Cranial Nerve III (3).