Look at the dot plot to answer the following question.

A dot plot titled How Old Were You When You Started Babysitting Question mark goes from 10 to 16. 10 has 2 dots, 11 has 3 dots, 12 has 3 dots, 13 has 6 dots, 14 has 2 dots, 15 has 1 dot, and 16 has 1 dot.

How many more people started babysitting when they were 13 rather than 12?
3
6
12
13