I have a 1099 B.....bought investments with inherited money so do I select that I bought the investments or that I inherited them?

if you used inherited cash to buy stocks there is no step-up. they are not inherited. your acquisition and sales dates are the trade dates for the buys and sells.   it's only if you inherited the actual stocks that you can use inherited as acquisition date.

You bought them.  How you received funds to buy the investments is not relevant.