To answer this question, "acerbity" refers to the quality of being bitter, harsh, or sharp in speech, tone, or manner. Therefore, the correct answer is D) Bitterness of speech.
Let's go through each option to understand why it is correct or incorrect:
Option A) Move faster - This option is incorrect because "acerbity" does not refer to the speed of movement.
Option B) Admitting a fault - This option is incorrect because "acerbity" does not involve admitting a fault.
Option C) Peak - This option is incorrect because "acerbity" does not relate to reaching a peak or summit.
Option D) Bitterness of speech - This option is correct because "acerbity" refers to the quality of being bitter, harsh, or sharp in speech, tone, or manner.
The correct answer is D) Bitterness of speech.