Mann-Whitney Utest be preferred

A group of high-risk automobile drivers (with three moving violations in one year) are required, according to random assignment, either to attend a traffic school or to perform supervised volunteer work. During the subsequent five-year period, these same drivers were cited for the following number of moving violations: NUMBER OF MOVING VIOLATIONS
TRAFFIC SCHOOL VOLUNTEER WORK 0 26
0 7
15 4
9 1
7 1
0 14
2 6
23 10
7 8
a. Why might the Mann-Whitney Utest be preferred to the t test for these data?
b. Use Uto test the null hypothesis at the .05 level of significance.
c. Specify the approximate p-value for this test result.