Card fronts have a color illustration of the player, surrounded by a white border. At the bottom is given the player's name, position, team, and league.
Card backs for this set feature the heading Base Ball Caramels then list the Pittsburgh Pirates cards in the block of text to the upper left, then the Washington Senators to the upper right, then the Boston Red Sox below these.
These card backs are actually how a collector can differentiate between Sets A through C of the E91 American Caramel cards. At the bottom is the ad for the issuing product, 'Manufactured only by the American Caramel Co.'
Note that a lot of the artwork on these cards are not necessarily meant to represent the specific personalities, but just sort of generic baseball players; the same artwork was used for the cards of different ones. Prominent players in Set C include:
T. H. [Tris] Speaker
Hans [Honus] Wagner