C. I presume the veterinarian is the person in charge of this rally for animal rights.
Explanation:
The word "presume" refers to taking something for granted. It also implies that the proposition is taken as true simply because there is no real evidence to point to the contrary. In this sentence, the person "presumes" that the veterinarian is the person in charge of the rally for animal rights. This is logical, as a veterinarian most likely cares about animal rights, and would therefore be a likely person to be in charge of such a rally.
