What is the quotient of the expression the quantity 28 times a to the fourth power times b plus 4 times a to the second power times b to the second power minus 12 times a times b end quantity divided by the quantity 4 a times b end quantity? 7a3 + ab + 3 7a3 + ab − 3 7a3 + 4ab + 8 7a3 + 4ab − 8