Final answer:
The correct action by the client using crutches is adjusting the crutch height for proper fit, ensuring a wide base of support and an appropriate center of gravity for balance.
Step-by-step explanation:
The client demonstrates proper use of crutches by adjusting the crutch height for proper fit. Proper use of crutches requires that the crutches are adjusted to the individual's height to ensure that they can bear weight appropriately and maintain balance without risking further injury. When a person is using crutches, they are intentionally altering their base of support and center of gravity to accomplish stability. A wide base of support and a properly adjusted center of gravity contribute to maintaining balance, as indicated in the concept where people adjust their stance to maintain balance, such as a father leaning forward when carrying his son piggyback. Therefore, the client is not demonstrating proper use by leaning forward while walking, using the crutches under the arms potentially putting pressure on underarm nerves and blood vessels, or bearing weight on the injured leg, as this could impair healing.