Step-by-step explanation:
well, what does your own logic tell you ? just think logically.
of course it is X || Z.
what else could it be ?
this is similar to questions like
if A > B, and B > C, then what does that say about A and C ?
right, A > C.
same thing for A=B, B=C, then A=C.
but it does not work with every relationship. so, be careful and just use basic logic - but that you will have to use.
