Ans b- Azathioprine

Cyclosporine is  immunomodulator indicated for second-line therapy in the case of severe, steroid refractory ulcerative colitis. Treatment is usually initiated after 3 to 5 days of failed steroid response

Tacrolimus is appropriate as second-line therapy in patients with severely active ulcerative colitis unresponsive to steroids.

The use of various anti–tumor necrosis factor-α  (TNF-α) monoclonal antibodies ( infliximab)  is well supported in the case of
severe ulcerative colitis refractory to steroids.