@pmv231, I was able to see all of the answers on this one, so try restarting your device, the app, or both.
We have
X-->A C-->/Z /Z-->/Z
Our job is to figure out the conclusion. Let's first take the contrapositives of each statement:
X-->A (/A-->/X) C-->/Z (Z-->/C) /Z-->/A (A-->Z)
Notice that if we take the first statement, we can combine it with the contrapositive of the third statement and the contrapositive of the second statement to create a transitive chain:
X-->A combined with A-->Z and Z-->/C yields
X-->Z-->Z-->/C
So we can conclude that X-->/C or C-->/X. Thus, D is the correct choice.
