Final answer:
The exercise that represents a functional task for the knee joint is C. Squats, because it is a compound movement that closely mimics everyday activities and engages multiple muscles that stabilize the knee.
Step-by-step explanation:
The exercise that represents a functional task for the knee joint is C. Squats. This exercise involves a compound movement that closely mimics the motions of everyday activities, such as sitting and standing, which require knee flexion and extension. The functional movement of squats engages the quadriceps, hamstrings, and gluteal muscles, making it highly beneficial for enhancing knee joint stability and overall leg strength.
On the other hand, exercises like leg extensions primarily target the quadriceps without the involvement of other muscles that stabilize the knee, which may not translate as effectively to real-world functional tasks. Similarly, while leg press and calf raises do engage multiple leg muscles, squats remain the exercise that most closely replicates the complex, multi-joint movements needed for day-to-day knee function.