The payables turnover ratio is calculated as Purchases divided by Average Trade Payables. Here, Cost of Sales is used as a proxy for Purchases. The calculation is as follows:

$\text{Payables Turnover} = \frac{\text{Cost of Sales}}{\text{Average Trade Payables}} = \frac{1,800}{(180 + 220) / 2} = \frac{1,800}{200} = 9$

• Option A (9) is correct because it accurately uses the average trade payables and cost of sales.
• Option B (10) is incorrect because it uses the ending accounts payable instead of the average.
• Option C (12) is incorrect because it incorrectly uses revenue instead of cost of sales in the numerator.

This ratio measures how efficiently a company pays its suppliers, with higher values indicating more frequent payments. The assumption is that all purchases are made on credit.