It Can Be Difficult to Stay Focused When You Are

It can be difficult to stay focused when you are listening to someone because:

A) Most people speak at about 130 words per minute.
B) People who speak at 200 words per minute are virtually unintelligible.
C) You can think at 500 words per minute, which is must faster than the person's speaking capacity.
D) The surrounding environment is full of distractions.