If a River Is Constantly Moving and Sense Experience Is

Multiple Choice

If a river is constantly moving and sense experience is veridical, then everything is in flux. If sense experience is veridical, but not our only means of knowledge, then not everything is in flux. So, if a river is constantly moving and sense experience is veridical, then the senses are our only means of knowledge.
-Working backward from the conclusion of this argument, which of the following is the most likely justification of the last step of the derivation?

A) Impl
B) Equiv
C) Taut
D) Exp
E) HS