Final answer:
A client with a C4 complete spinal cord injury can use a universal cuff to play cards, as it helps individuals with limited hand function to hold items.
Step-by-step explanation:
In addition to a card holder, a client with a C4 complete spinal cord injury can use a universal cuff to play cards. A universal cuff is an adaptive device designed to assist individuals with limited hand function to hold items such as utensils, pens, and in this case, playing cards. It is typically a band or strap that fits securely around the hand or wrist, with a pocket or slot to insert objects.
The other options, such as a mouth stick, wrist splint, and Dycem mat, serve different purposes. A mouth stick can be useful for someone with no hand function at all, but it is generally more suitable for tasks like pressing keys on a keyboard or turning pages. A wrist splint is more for wrist stabilization and would not typically aid in holding cards. Dycem is a non-slip material often used to prevent objects from sliding but would not help in gripping cards.