Answer
$\rm 0\;V,3\;V,0\;V,3\;V$
Work Step by Step
We can see, from the given figure, that the top wire has the same potential as the top of the battery while the bottom wire has the same potential as the bottom of the battery.
Thus,
$$\Delta V_{12}=\bf 0\;\rm V$$
$$\Delta V_{23}=\bf 3\;\rm V$$
$$\Delta V_{34}=\bf 0\;\rm V$$
$$\Delta V_{14}=\bf 3\;\rm V$$
