Assuming that all 12 questions are answered correctly,

1+2+3+…+ 12=78 (point),

(78-60)÷2=9 points,

That is, the sum of the wrong questions is 9;

So Xiao Ming's number of wrong questions may be 6.2 1, 5.3 1, 4.32;

So choose: b, c, d.