Correct Option (D)
The passage explicitly states, "Proneness to exaggerate, to suppress or modify the truth, wittingly or unwittingly, is a natural weakness of man, and silence is necessary in order to surmount it." Therefore, silence is presented as a necessary discipline to overcome the human tendency to overstate or distort facts.
Incorrect Options:
- Option (A) constitutional shyness: The author describes constitutional shyness as an advantage, referring to it as a "shield and buckler" that has aided personal growth and discernment of truth. It is not depicted as a weakness requiring silence to be surmounted.
- Option (B) hesitancy in speech: The author views hesitancy in speech as a beneficial trait that fostered self-restraint and economy of words. Silence is not proposed as a means to overcome this characteristic, but rather as a related positive outcome of disciplined communication.
- Option (C) suppression of thoughts: The passage advocates for restraining thoughts and carefully measuring words to prevent thoughtless speech. Silence is presented as a tool for thoughtful and disciplined expression, not for the complete suppression of thoughts.