Big Book Test 6: Section2 Q6

I am getting confused between two contrasting words here… “Although” and “In Reality”…

How I approached It:

  1. As his interest is almost non-existent(Last Line), implies something similar in 2nd Blank…
    i) If interest is redundant (Superfluous), it cannot be non-existent, Hence A is wrong.
    ii) If interest is preemptive (impeding/hindering), it cannot be non-existent, Hence B is wrong.
    iii) Dispassionate(Unbiased/Rational) interest cannot be non-existent, Hence E is wrong.
  2. Because Although is implying contrast and in second part, he is not showing interest(Negative), hence In first part he must be showing interest or something Positive. Therefore I eliminated D because Feigned is negative word, though Perfunctory is making sense perfectly for second blank.

So I chose C. May you help me understand Why contrast of Although did not work here? I am getting confused between two contrasting words here, “Although” and “In Reality”.