The question asks for a solution to ensure the production MySQL database on Cloud SQL is available 24/7 during the year-end holiday shopping season by skipping routine maintenance during that period. Option A is correct because it precisely defines a maintenance window on Sundays between 12 AM and 1 AM, which is when traffic is slow, and it denies maintenance periods between November 1 and January 15, covering the holiday season. Option B extends the maintenance window unnecessarily and the denial period beyond the holiday season, which is not required. Option C suggests using Cloud Composer for a task that can be directly managed within Cloud SQL's settings, making it overly complex. Option D proposes using Cloud Scheduler to start maintenance, which is not the most straightforward method for managing maintenance windows in Cloud SQL. Therefore, the most straightforward and correct answer is A.