In the case with positive powers, the balance of three variables looks the following way:
- When \(x>y>z>0\), in the fourth power the same inequality is going to remain, regardless of whether the numbers are integers or decimals below 1.
- When \(0>x>y>z\), in the fourth power all signs change to the opposite, preserving the order, again regardless of whether the numbers are integers or decimals above -1:
\(0>-1>-2>-3\), but \(0<(-1)^4<(-2)^4<(-3)^4\)
This means, obviously, that both
Option I and Option II are possible, pretty much for any number available.
With
Option III the situation is trickier, as it changes the order of ascendance among the variables.
The only case when this is possible is when zero 'cuts into' the sequence of numbers, making some of them positive, and others - negative. For instance:
\(2 > 0 > -1\), but \(16 > 1 > 0\) - so the last two numbers switched places.
However, as can be seen from the example above, zero can only be in the middle - because when zero is in the first place, all the other numbers are negative, and we see the simple case discussed above.
Also, while it's possible to switch places of X and Y, like \( x>y\) with \(1>-2\), but \(x^4<y^4\), as \(1^4<(-2)^4\). However, Z will always travel from the lowest to the highest position, so there's
no way to preserve \(z^4\) as the smallest member.
Therefore,
Option III is impossible.
The correct answer is therefore C. I and II only.