Final answer:
Sara needs to spend at least $300 to meet Sky Zone's requirement.
Step-by-step explanation:
In this question, Sara is planning her son's birthday party at Sky Zone, which requires parties to spend at least $300 per event. To determine how much money Sara needs to spend, we look at the given options: $200, $250, $300, and $350.
Since the requirement is to spend at least $300, option C, $300, is the correct answer. This means that Sara needs to spend at least $300 to meet Sky Zone's requirement.