When inviting your elderly aunt to your house for a family gathering, the most appropriate imperative sentence would be:
C. ¡Venga a nuestra casa!
Here's why:
1. **Respectful Tone**: Using "Venga" (formal singular imperative form of venir) shows respect towards your elderly aunt, which is important when addressing an older family member.
2. **Clarity and Directness**: The imperative form "Venga" is clear and direct, making it easy for your aunt to understand the invitation.
3. **Politeness**: In Spanish, using the formal imperative form is a polite way to address someone older or in a position of respect, such as an elderly aunt.
4. **Correct Grammar**: "Venga a nuestra casa" is grammatically correct and conveys the invitation appropriately for a family gathering.
Therefore, when extending the invitation to your elderly aunt, "¡Venga a nuestra casa!" is the most suitable choice.
