Lena found the greatest common factor (gcf) of 24ab2c3 and 30a2b3c2 to be 6abc2 by using these steps: step 1: gcf of 24 and 30 is 6 step 2: highest shared power between a and a2 is a step 3: highest shared power between b2 and b3 is b step 4: highest shared power between c3 and c2 is c2 in which step did lena make a mistake? options: step 1 step 2 step 3 step 4