GST 9 & 9C

box 6 Require bifercation in Input capital service so this bifercation it's as per 3b or as per 2a (assuming 2a is right) because my 2a is less..
if I show as per 2a then in 9c difference will come so that difference will be payable..
if I got for 3b bifercation then difference not come in 9c so guide me?