To find out how many comic books Cindy has, we can set up the equation based on the information provided. Since Shernice has 84 comic books, which is 12 times the number of comic books Cindy has, we can express that relationship as:
\[ 84 = 12 \times c \]
So, the correct equation representing how many comic books Cindy has is:
84 = 12 x c