What Medicare deductible do I use if retired? Medicare B, C or D

Are you asking what premium payments you can deduct?  You can deduct all of them. 

Do you receive Social Security benefits?  If you do, then the Medicare is deducted from your benefits and it is listed on your SSA1099 that you get from Social Security in January.  When you enter the information from the SSA1099 into the income section, the medicare flows over to the Medical Expenses for the deduction. So you do not need to enter it again.