PTA.S1.Q16 Giordano Bruno

cest_la_vie

I identified the premise and conclusion as the following:

P1: Spy is identified as the only clergyman working at the French embassy
P2: Bruno had been ordained a member of the clergy long before he started work at the embassy
Concl: Bruno must have been the spy

I narrowed down to A and C and eventually picked C, which was the wrong answer.
I thought C was correct since his lack of French skills meant that he lacked the skillset that the spy had. On the other hand, I eliminated A because "not being dressed or functioned as a member of the clergy" is insufficient to prove Bruno wasn't a clergyman at all. He might have been an inactive member but could still have retained his clergyman title. I still don't see why C is wrong and A is correct. Can anyone walk me through the correct reasoning?