Correct Answer - Option 3 : 6
According to the given information;
The black cards are either clubs or spades.
While the red cards are either diamonds or hearts.
Let the number of spades = x
Then, the number of clubs = (7 - x)
Number of diamonds = 2 × number of spades = 2x
Number of hearts = 2 × number of diamonds = 4x
Total number of cards = x + 2x + 4x + (7 - x) = 6x + 7
Therefore, 6x + 7 = 13
6x = 6
x = 1
Number of clubes = (7 - x) = 6
Hence, "6" is the correct answer.