Carriage inwards refers to the cost of transportation incurred by a business in bringing goods purchased from a supplier to their own premises. This cost is typically included as part of the cost of the goods purchased, and is therefore shown on the debit side of the Trading Account. The Trading Account is a financial statement that shows the calculation of Gross Profit or Loss for a business by deducting the cost of goods sold from the sales revenue. So, the correct answer is: "debit side of the trading account".