I have emplyoment income (less than 25k), savings account interest, dividends from stock and a disbursement from closing an inherited IRA-BDA to report.

I was born in the US, never lived anywhere else.

I know I have to file a schedules B, D, K ( one stock was a partnership) and form 8949

But which Federal Tax form do I use and what is the difference between IRS forms 1040 and 1040A?

The Schedule D and Form 8949 mandates that you file Form 1040; Form 1040A is NOT an option.