Please help me for my finals!! I'll do anything

(A)

Choice (B) is not the right answer because I

it's only 3rd order. But because f(x) goes to negative infinity when x goes to positive infinity means that the right answer is (A).

If you know Heron's formula, this is easy.

where is the semiperimeter of the triangle.

The area is also equal to half the product of the base and height of the triangle, which happen to be

so the answer is B.