The lunar cycle is about how many days long?

• A. 28 days
• B. 29 days
• C. 30 days
• D. 31 days

Answer: (C)

The lunar cycle is the time it takes for the Moon to return to the same phase, such as from new moon back to new moon. This cycle is about twenty-nine and a half days long. When you’re choosing among whole-day options, the one that best matches this length is the estimate describing roughly a calendar month. Since the cycle is just a bit under thirty days, rounding to the nearest whole day gives a duration that closely matches a month, which is why that option is the best pick. Remember that the exact value isn’t a neat whole number, but the closest whole-day approximation is about a month.