D 2,050
Explanation: Since 82% of customers who purchase an item on sale also purchase at least one item not on sale, we can determine the number of customers who will also purchase at least one item not on sale by multiplying 2,500 (number of customers who purchase an item on sale) by 82%:
2,500 * 0.82 = 2,050
Therefore, 2,050 customers will also purchase at least one item not on sale.