Answer: A
Explanation:
You want to make them both have common denominators. What number does the denominators both go into? Thats easy, its 60.
Multiply 7/12 by 5/5 to get 35/60
Now multiply 4/15 by 4/4 to get 16/60
You need to add a negative number to 35/60 in order to get 16/60
Do 16-35 to get -19/60