Concept: This question tests your understanding of the classification of muscles based on their control by the nervous system, specifically distinguishing between voluntary and involuntary muscles.

Why (B) is correct: The muscles of the urinary bladder are primarily composed of smooth muscle, which is under the control of the autonomic nervous system. This means its contractions (like those involved in urination) are largely involuntary and not consciously controlled.

Why other options are wrong:

• (A) Pharynx: The muscles of the pharynx are involved in swallowing, which is initiated voluntarily.
• (C) Anterior end of oesophagus: The upper part of the oesophagus contains skeletal muscle, allowing for voluntary initiation of swallowing.
• (D) Tongue: The tongue is a muscular organ composed of skeletal muscle, allowing for voluntary movements involved in speech, chewing, and swallowing.

Common Mistake: Students might confuse the initial voluntary act of swallowing with the subsequent involuntary peristalsis in the oesophagus.

NEET Tip / Mnemonic: Remember that skeletal muscles are generally voluntary, while smooth muscles and cardiac muscles are involuntary. Think of actions you can consciously start or stop (voluntary) versus those that happen automatically (involuntary).

Correct Answer: (B)