George owns twelve audio compact discs. If he takes two of them to play on an upcoming car trip, how many different pairs of compact discs could he choose?  Choose the correct choice from the following.
A) 144 B) 132 C) 72 D) 66 E) 36
C212=66   Answer: 66.
<result>D</result>
George owns twelve audio compact discs. If he takes two of them to play on an upcoming car trip, how many different pairs of compact discs could he choose?