I would think its a classic case of pick the ‘most right’ answer. I myself would pick ‘B’. If you set up the example of two vessels passing within 1 mile of each other on inland waters, they sound the appropriate signal, and pass with no risk. When passing signals are made and understood, that should negate the risk of doubt/collision.
However, if you do lose your challenge, you only have to take the ROR again, not the 6 modules. You would have to take all 6 again if you let something like 60 or 90 days pass without re testing.