7c+5(c-d)-d =a. 6(2c-d)b.12cc.4(3c+d)d.2(6c-5d)e.2( 6c-d)

= 7c + 5(c - d) - d
multiply 5 by parentheses

= 7c + (5*c) + (5*-d) - d
multiply in parentheses

= 7c + 5c - 5d - d
combine like terms

= 12c - 6d
factor out a 6 from both terms

= 6(2c - d)

ANSWER: (A) 6(2c - d)

Hope this helps! :)