A student investigates the thermochemical properties of three gaseous constitutional isomers with the molecular formula \(\text{C}_5\text{H}_{12}\). The standard enthalpies of formation, \(\Delta H_f^\circ\), for the isomers at \(298 \text{ K}\) are given in the table below.

Isomer	Structural formula	\(\Delta H_f^\circ\ (\text{kJ/mol})\)
\(\text{X}\)	\(\text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{CH}_3\)	\(-146\)
\(\text{Y}\)	\((\text{CH}_3)_2\text{CHCH}_2\text{CH}_3\)	\(-154\)
\(\text{Z}\)	\(\text{C}(\text{CH}_3)_4\)	\(-168\)

All three isomers undergo complete combustion with excess \(\text{O}_2\text{(g)}\) according to the following equation:
\[ \text{C}_5\text{H}_{12}\text{(g)} + 8\,\text{O}_2\text{(g)} \rightarrow 5\,\text{CO}_2\text{(g)} + 6\,\text{H}_2\text{O(l)} \]

Which of the following correctly ranks the isomers in order of the magnitude of heat released per mole of isomer completely combusted, from greatest to least, with the correct justification?