20 POINTSSS!!
Which of the following sets of Real Numbers are Counting Numbers?

A. { 0, 1, 2, 3, 4, 5, 6, 7, 8, 9 }
B. { 1, 2, 3, 4 ... }
C. { 0, 1, 2, 3, 4 ...}
D. { ...-2, -1, 0, 1, 2 ... }