This answer is correct because it is a recommended time to refresh the full copy sandbox. Refreshing the full copy sandbox after each major release to production can help ensure that the sandbox has the most updated data and metadata from production, which can facilitate testing and development activities. Refreshing the full copy sandbox too frequently can be costly and time-consuming, as it consumes a lot of storage space and requires data masking or anonymization. Reference: https://help.salesforce.com/s/articleView?id=sf.data_sandbox_implementation_tips.htm&type=5