[A]
Inversely proportional to the product of their masses and directly proportional to the square of their distance apart
[B]
Inversely proportional to the product of their masses and directly proportional to their distance apart
[C]
Directly proportional to the product of their masses and inversely proportional to their distance apart
[D]
Directly proportional to the product of their masses and inversely proportional to the square of their distance apart