For HSA contribution box 12 what line do you enter?12a,b,c or d

[MindyB]

HSA contributions are reported on your W-2 Box 12 Code W.  

The other 3 codes you mentioned are not HSA codes.  They are as follows: A- uncollected social security tax on tips, B- uncollected Medicare tax on tips, C- life insurance, D- 401(k) deferrals. See: W-2 Instructions for a complete list of codes.

[NCperson]

@Eve8 there is a point along the way where Turbo Tax asks if you made any DIRECT contributions to your HSA; this does NOT include what is listed on your W-2.  

A DIRECT contribution is when you send money outside your paycheck to the HSA.