The trading account is a statement that shows the gross profit or gross loss of a business over a particular period. It takes into account the direct expenses and direct incomes of the business.
Out of the given options, "carriage inwards" can be considered a trading account item. Carriage inwards refers to the cost incurred by a business in bringing goods purchased into its premises or warehouse. This cost is a direct expense and is taken into account while calculating the cost of goods sold (COGS) and eventually the gross profit or loss of the business. Therefore, carriage inwards is a trading account item.
On the other hand, discount allowed, discount received, and carriage outwards are not direct expenses or incomes of the business, and therefore, they are not considered trading account items. Discount allowed and discount received are usually recorded in the profit and loss account, while carriage outwards is a part of the statement of profit or loss.