Let Min Number of cards be N.
Given,
No of holes (holes) = 4 (since there are 4 suits in pack of 52 cards)
Required no of cards (R) = 3 (since 3 cards of same suit required)
Using Generalized Pigeon Hole,
$\left \lceil \frac{N}{holes}\right\rceil$ = R
$\left \lceil \frac{N}{4}\right\rceil$ = 3
So minimum N satisfying above equation is 9 ( since $\left \lceil \frac{9}{4}\right\rceil$ = 3).
Hence Option C is correct.