Which Statement Is an Example of Habituation

Which statement is an example of habituation?

A) As one goes to bed, one hears the bathroom faucet dripping. The sound becomes more annoying as the night goes on.
B) A person's car spins out on the ice in the winter. Afterwards, the person is much more nervous while driving.
C) An experienced shepherd can quickly distinguish his sheep from one another.
D) On entering a room, one notices the soft hum of a fan, but after being there for a while, one no longer notices the sound.