Explanation:
a. Randomly selecting a red card = 

have 26 card choices
B. Randomly selecting a 7, 8, 9, or 10 = 

(have 4*4 card choice)
C. Randomly selecting the 6 of diamonds = 

(only 1 card choice) 
D. Randomly selecting a card that is not a king 

1 - all possibility that can select the king