Since x is related to y and y is related to z, to relate universe x and universe z we have to compute max-min composition:
x
1z
1= max(min(0.7, 0.9), min(0.5, 0.1))
= max(0.7 0.1)
= 0.7
x
1z
2= max(min(0.7, 0.6), min(0.5, 0.7))
= max(0.6, 0.5)
= 0.6
x
1z
3= max(min(0.7, 0.2), min(0.5, 0.5))
= max(0.2, 0.5)
= 0.5
x
2z
1= max(min(0.8, 0.9), min(0.4, 0.1))
= max(0.8, 0.1)
= 0.8
x
2z
2= max(min(0.8, 0.6), min(0.4, 0.7))
= max(0.6, 0.4)
= 0.6
x
3z
3= max(min(0.8, 0.2), min(0.4, 0.5))
= max(0.2, 0.4)
= 0.4
So, option (C) is correct.