SB: $3.09 (Hero)
I realized I don't really know how to form a range when facing a 4bet from BU after 3betting from the SB. 77 felt lose to a call to me. I had another hand similar to this in the same session, ATo, and again I realized I'm not sure how to respond to these situations.
I understand the idea behind playing 3bet or fold from the SB, but what I'm not sure about is what to do when you get 4bet.
How do you guys form ranges here? Linear? Polar? Against an unknown?