I’m 99% sure the answer is:
c: 2t - d = 260
t - d = 320
The correct answer is:
[B]: "

" .
__________________________________________________________Consider choice [A]: 
;
=

;
= 2 ; "2 ≠ -2" ; so we can rule out: "Choice [A]" .
__________________________________________________________Consider choice [B]: 
;
=

;
= "-2" ; Yes!
→ Let us proceed with the final answer choice ;
__________________________________________________________Consider choice [C]:

;
=

;
= 2 ; "2 ≠ -2" ; so we can rule out: "Choice [C]" .
__________________________________________________________The correct answer is:
[B]: "

" .
__________________________________________________________
Answer:
Step-by-step explanation:
For this case we are interested on the region shaded on the figure attached.
And we can find the volume with the method of rings.
The area on this case is given by:
![A(x) = \pi [f(x)]^2 = \pi r^2 = \pi [3x]^2 = 9\pi x^2](https://tex.z-dn.net/?f=%20A%28x%29%20%3D%20%5Cpi%20%5Bf%28x%29%5D%5E2%20%3D%20%5Cpi%20r%5E2%20%3D%20%5Cpi%20%5B3x%5D%5E2%20%3D%209%5Cpi%20x%5E2)
And the volume is given by the following formula:

For our case our limits are x=0 and x=2 so we have this:

And if we solve the integral we got this:
![V= \pi [\frac{x^3}{3}]\Big|_0^{2}](https://tex.z-dn.net/?f=%20V%3D%20%5Cpi%20%5B%5Cfrac%7Bx%5E3%7D%7B3%7D%5D%5CBig%7C_0%5E%7B2%7D)
And after evaluate we got this:
![V=\pi [(\frac{8}{3} )-(\frac{0}{3} )]](https://tex.z-dn.net/?f=%20V%3D%5Cpi%20%5B%28%5Cfrac%7B8%7D%7B3%7D%20%29-%28%5Cfrac%7B0%7D%7B3%7D%20%29%5D)