Where do I enter EPP stock discount in Turbotax Deluxe?

I have an EPP program at work where I get 15% off my stock purchase . (The Fair Market Value of the stock minus my actual Cost of the stock) .  I sold the stock in 2021.

Do I add the 15% discounted amount into the cost basis that was provided on my 1099B?   - or 

Do I check the box that says "An adjustment is required for a reason not already covered" and then enter the 15% discounted amount on the next page?  - or - 

If not, where should I enter the 15% discounted amount for the stock sold?