Correct Option (A)
While the author acknowledges that excessive talking constitutes a waste of time and that his measured speech has spared him such waste, the passage does not present the intention to avoid wasting time as the direct reason for the absence of thoughtless words. Instead, the primary mechanisms cited for this outcome are the practice of economy of words, the habit of restraining thoughts, and the natural hesitancy in speech.
Incorrect Options:
- Option (B) He believes in the economy of words: The passage explicitly states, "Its greatest benefit has been that it has taught me the economy of words." This is presented as a direct reason for his careful expression.
- Option (C) He believes in restraining his thoughts: The author clearly mentions, "I have naturally formed the habit of restraining my thoughts." This habit is a direct contributor to preventing thoughtless speech.
- Option (D) He has hesitancy in his speech: The passage indicates that his "hesitancy in speech" led to the development of the "economy of words," thereby influencing his careful selection of words and preventing thoughtless utterances.