Hi Medas, B tells us that one person thinks there is no difference between two things, C tells us that two people disagree about the existence of a relationship between those two things. To state that there is no difference between two things is not necessarily the same as tromsay they are two facets of the same phenomenon.
By analogy, snow and rain are facets of the same phenomenon (precipitation). Saying that snow and rain are related would be one claim (akin to C) but to say that there apis no difference between snow and rain would be very different, and akin to B.
Also, B only discusses Antonio's view, while C discusses both of the views.