There are different types of arthritis. They are often classified by the
number of that are involved.
A. joints
B. muscles
C. bones

Arthritis effects the joints, so I’d assume it’s A.

Explanation:

There are 4 types of arthritis; Degenerative arthritis, inflammatory arthritis, metabolic arthritis, and infectious arthritis. Arthritis can cause inflammatory damage, or degenerative damage (meaning it may breakdown your joints).

Hope this helps!

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