Aden has served as a temporary seat for Yemen's internationally recognized government. Which city remains Yemen's national capital?

Explication

Sana'a remains Yemen's national capital. Aden's use as a temporary government seat explains the common confusion, but that temporary function does not replace Sana'a in this national-capital question. Sana'a remains the constitutional national capital, while Aden serves as the temporary seat of the internationally recognized government.