White declined the benko gambit. What now?

So, I usually play the old benoni, and if white pushes the pawn I want to play Nf6, hoping for benko transposition. But what if it doesn't happen? What if white plays like this

or any other non-c4 move. What are the ideas for black here? 

This is LITERALLY why the Old Benoni is called the Old Benoni. It’s old, it’s outdated, and if White does this Black is essentially sunk already. Instead, play the modern move order which goes like this:

Oh no. White declined the Benko Gambit. That may be the first time..... the world as we know it may never be the same.

check out Hanging Pawns video on the old Benoni on YouTube. he goes into some of these lines. with out C4 by white you will not play a Benko. And black playing b5 anyway may just be a waste of a move. one of the problems with the Old Benoni is white can get e4 in very easily and possibly push to e5. the Modern Benoni deals with e4 by white much better by playing e6. And having a half open e file. the drawback is the backwards pawn on d6. the old Benoni keeps the pawn on e7.

If you want to play the benko, play the regular Benoni.

Also shout-out to hanging pawns

play it like a benoni

you can play e6 whenever you want. just take advantage that white never got c4 in and go for normal plans

just know that when you play e6 your d6 pawn can get heavily weakened and could collapsed to the Bf4-Ng5 plan (or the Bf4-Nd2-Nc4)

also the forum name makes it sound like if its the actual benko gambit declined