Here is my thought process:
Kapp=apparent association constant=(comp1)^2/(comp2) If you increase Kapp, this means increased affinity to comp1.
so as comp2 increases, the Kapp should decrease. (because its an inhibitor)
I think you have Kapp and Km mixed up.
ITC exp: Comp1+ProtA results in large K1
CITC exp: Comp1+ProA+10mMComp2(competitive inhibitor) results in Kapp=K1 (the reason why we observe this is, I think like
@theonlytycrane said is that: we may not have a very concentrated comp2 (inhibitor)) If we did have concentrated comp2 (enough to compete over comp1, then we would expect Kapp<K1)
The Q-stem asks you to increase K1 to become greater than Kapp, or in other words, decrease Kapp, so we can choose D=increase comp2 concentration.
Let me know if that helps
@drobgyn32