Hey Lubna —
This is a tough q — not sure how you set up your diagram (I created three frames around the QT and SR options) but hope this explanation makes sense —
The (S, R1) duo has to go in F or in I.
To see if (A) must be true, we can try putting (S, R1) in I (or just look at that frame if you set it up that way).
If (S,R1) is in I, (Q, T1) must be in G. That pushes the second R and the second T into the final grouping, L.
However, we also must place another Q, and Q can’t go in F. Q, therefore, also would have to go in the final grouping, and we don’t have enough space.
So, if we put (S, R1) in I, we can’t satisfy all of the rules. Therefore, R must be in F.
I imagine there might be some other ways of seeing/explaining this more clearly, but that’s how I did it when I just tried it — hope that made sense, and if you have any follow-up or need clarification let me know.