I suspect 4/2 should actually be 4/3, since 4/2 = 2, while 4/3 would make V the volume of a sphere with radius r. But I'll stick with what's given:





In Mathematica, you can check this result via
D[4/2*Pi*r^3, r]
I think the answer is D. The other answers are unreasonable. Wyatt would not get the promotion and just because Tammy's lowest value is bigger than Wyatt's doesn't mean that Tammy gets the promotion. The only reasonable answer is D.
Option c is correct. Use special right triangles and you will findout why. Hint:Use the 45-45-90 special right triangle's properties.