According to the histogram of frequency distribution, the number of students in [y0,50] is 60× 0.0/kloc-0 /×10 = 60× 0.1= 6.

The number of people whose grades fall in the interval [30, 100] is 60×0.005× 10=3.

Two students were randomly selected from the students whose grades were [y0,50] and [30, 100].

C23=36 cases,

Two people were selected in the same score segment, with a total of C23+C26 = 18 cases.

Then the probability that they are in the same fraction is p = 1836 = 12.

So choose: a.