Least audible sound for most of the human ear is : A. 10.0 µ bar B. 0.0002 µ bar C. 0.005 µ bar D. 5.0 µ bar

The correct answer is B. 0.0002 µ bar.

The least audible sound for most of the human ear is 0.0002 µ bar, which is also known as the threshold of hearing. This is the lowest sound pressure level that a human ear can detect at 1 kHz. The threshold of hearing varies from person to person, and it also decreases with age.

Option A is incorrect because it is too high. The threshold of hearing is much lower than 10.0 µ bar.

Option C is incorrect because it is too low. The threshold of hearing is not 0.005 µ bar.

Option D is incorrect because it is too high. The threshold of hearing is not 5.0 µ bar.