while filling DS-160 I gave specific date of return from the usa

I got my visa approved.Now, will the immigration officer write ‘D/S’ or a particular date? If he writes a particular date, can I get OPT? I got my visa for 22 months only i.e visa expires on the date mentioned on my i20.how can i proceed with this?

Usuaully they write D/S when putting the immigration stamp for F-1 visa holders.

It will be a D/S stamp at port of entry, that entry stamp overrules any dates specified on any documents