While inflammation is associated with osteoarthritis, it typically occurs later in the disease process.

The initial step in osteoarthritis development is the breakdown of cartilage in the joint due to various factors, including mechanical stress.

Choice B rationale:

The primary cause of osteoarthritis is not bones rubbing against each other.

Instead, it is the degeneration of joint cartilage that leads to joint damage.

The rubbing of bones against each other may occur as a result of cartilage loss in advanced stages of the disease.

Choice C rationale:

Cartilage breakdown is indeed the initial step in osteoarthritis.

Over time, the loss of cartilage can lead to joint damage, pain, and stiffness, which are characteristic of the condition.

Choice D rationale:

Bone spurs can develop in osteoarthritis, but they typically form as a result of the ongoing joint damage caused by cartilage breakdown.

Bone spurs are not the initial event in the development of osteoarthritis.