It’s D.
Explanation: Since the area formula is A = bh/2, you would replace the variables with what you know. Since we know that the base is 4 and the area is 40, your equation would be 40 = (4)(h)/2. To solve, you would simplify the (4)(h)/2 to 2h because 4 divided by 2 is 2. You’re left with 40 = 2h and then you divide by 2 to get h by itself, 40 divided by 2 is 20, therefore the height is 20 inches.