Is it permissible for a Muslim woman to give food or water to non-Muslims at work?

It is permissible to show kindness to non-Muslims, as long as they are not hostile towards Muslims or aiding their enemies, based on the Almighty's saying: (Allah does not forbid you from those who do not fight you because of religion and do not expel you from your homes - from being righteous toward them and acting justly toward them. Indeed, Allah loves those who act justly). A Muslim is rewarded for such kindness, as mentioned in the description of the righteous: (And they give food, in spite of love for it, to the needy, the orphan, and the captive), and a captive could be a disbeliever.