Im trying to fill out my ssi survivor benefits info and it is asking about the medicare b,c or d premium. where would i find that?

Do you have an SSA-1099 form? That info would be on that form if you had Medicare premiums deducted from your benefits.

Your annual form SSA-1099 from the Social Security Administration will have that information. It will be found along the left hand "Description of amount in box 3 item" area.   These amount will automatically be added to medical expenses to count toward your itemized deductions.