If a spouse was a nonresident for the whole year, what is the impact on their California tax filing?

A spouse who is a nonresident for the entire year can still file separately for California taxes. While California allows certain residents and nonresidents to file as married filing separately, this option is available to a nonresident spouse as well, given that they may have California-source income or wish to report their income in a way that aligns with their tax obligations.

Filing separately can potentially provide clarity on tax liabilities, such as ensuring the nonresident spouse only pays taxes on income generated within California, rather than being taxed on worldwide income. This serves to limit their exposure to California state taxes, which is crucial for a nonresident.

In this context, the other options do not apply as effectively. For instance, not being able to file jointly does not preclude the option to file separately, and while it is true that federal taxes must be filed, it is incorrect to state that the individual is limited to only those since they also must address state tax responsibilities. Furthermore, declaring combined income does not apply to nonresidents because they are only responsible for California-source income rather than combined income from both spouses.