Simplify completely quantity 6 x minus 12 over 10 .
a. 2 open parentheses x minus 6 close parentheses over 5
b. 3 open parentheses x minus 2 close parentheses over 5
c. 6 open parentheses x minus 1 close parentheses over 5
d. 6 open parentheses x minus 6 close parentheses over 5