$${}^{n-1}C_r = (k^2 - 8) \; {}^{n}C_{r+1}$$ if and only if :

A

$$2\sqrt{2} < k \leq 3$$

B

$$2\sqrt{3} < k \leq 3\sqrt{2}$$

C

$$2\sqrt{3} < k < 3\sqrt{3}$$

D

$$2\sqrt{2} < k < 2\sqrt{3}$$