Choice A rationale:

Weight management is essential for overall health, but it is not primarily aimed at preventing joint stiffness in osteoarthritis.

Joint stiffness is a symptom of the disease and may improve with other interventions.

Choice B rationale:

Maintaining a healthy weight can support joint health and flexibility but may not directly increase joint flexibility in someone with existing osteoarthritis.

It is more about preventing further damage.

Choice C rationale:

Losing weight can relieve pressure on the joints and improve osteoarthritis symptoms significantly.

Excess body weight places additional stress on weight-bearing joints, such as the knees and hips.

Weight loss can reduce pain and slow the progression of the disease.

Choice D rationale:

Weight loss can have a positive impact on the progression of osteoarthritis.

It reduces the mechanical load on the joints and can slow down the degenerative process.