Lupus nephritis (type IV), what is the preferred immunosuppressant?

*For medical professionals to read and reference Xueba Challenge, waiting for you! For lupus nephritis (pathological type IV), the preferred immunosuppressant is A.
Cyclophosphamide B.
Methotrexate C.
Vincristine D.
Azathioprine E.
Tripterygium When the spondylitis progresses to an advanced stage, the ligaments connecting the vertebral bodies are calcified, like two bricks fixed with cement from the side, resulting in the appearance of bamboo-like changes in the spine, which is one of the characteristic manifestations of ankylosing spondylitis.
The aggravation of sacroiliitis increases (A pair), so this topic chooses
A.

② Osteoarthritis, rheumatoid arthritis, reactive arthritis, and systemic lupus erythematosus will not appear bamboo-like degeneration of the spine (B, C, D, E are not selected)
.

Link to the previous article: X-ray examination shows bamboo-like changes in the spine, what is the disease?