The correct answer is A: Global secondary index with Product ID as the partition key and Product Rating as the sort key. Using a global secondary index (GSI) allows you to create an index where the partition key can be different from the base table's partition key. By setting the partition key to Product ID and the sort key to Product Rating, you can efficiently query the top 10 reviews with the highest rating for a specific product. This is because the GSI will allow you to directly look up reviews for a given Product ID and sort them by Product Rating.