Work out X's full option set from the replaced rule and the Z and T counts first, then compare it directly against V's fixed set of digital camera and document viewer.
Six mobile phones, T, V, W, X, Y and Z, each carry at least one of three options: digital camera, music player and document viewer. V carries digital camera and document viewer. W carries digital camera and music player. W and Y share nothing, so Y carries only the document viewer. V and Z share exactly one option, and T carries fewer options than Z. For this question, the usual rule "X has more options than W" is replaced with "X and W have exactly two options in common," and we need the statement that must be false.
Let's summarize:
So the statement that must be false is that V and X have exactly one option in common.