During which festival did Romulus and his men kidnap the Sabine women?

The correct answer is Consualia. This festival, celebrated in ancient Rome, was dedicated to Consus, the god of granaries and stored grain, and was marked by festivities that included horse racing and agricultural celebrations. It is significant in Roman mythology as it is during this festival that Romulus and his men seized the Sabine women in order to ensure the future of their city by acquiring wives for themselves, which was a pivotal event in the founding of Rome.

In contrast, the other festivals listed are associated with different themes. Lupercalia is primarily a festival of purification and fertility, often linked with the celebration of the founding of Rome and the she-wolf that nurtured Romulus and Remus. Natalis Invicti is a festival celebrating the "birth of the unconquered sun," and is often associated with sun gods and later embedded into Christmas celebrations. Saturnalia was a week-long festival honoring Saturn, marked by public feasting and a temporary reversal of social roles, but does not relate to the abduction of the Sabine women. Thus, Consualia specifically aligns with the event in question, making it the correct choice.