Final answer:
China is the country that is large in area but has only one time zone, which is unique given its size and geographical span.
Step-by-step explanation:
The country that is large in terms of area but has only one time zone is China. Unlike countries such as the United States, which has multiple time zones like eastern, central, mountain, and western, China operates under a single time zone for the entire country. This is despite its vast land area and its geographical span which is quite comparable to that of the United States. All clocks across China keep Beijing time, which results in some regions like Tibet experiencing sunrise when it is already midmorning according to the official time.
China manages its single time zone despite the practical differences in solar time across its territory. This decision has various implications, such as differing daylight hours, particularly in the country's western regions.