4.1 Demand for an item is constant at 400 units a month. The reorder cost and delivery charge amount to \( £ 1,240 \) and the cost of holding stock is 30 per cent of value a year. A supplier quotes the following prices
\begin{tabular}{lcccc}
Order quantity & \( 0-1,499 \) & \( 1,500-1,999 \) & \( 2,000-2,499 \) & 2,500 or more \\
Unit cost & \( £ 12.60 \) & \( £ 12.20 \) & \( £ 11.80 \) & \( £ 11.20 \)
\end{tabular}
A second supplier quotes a basic price of \( £ 12 \), but with a discount to \( £ 11.40 \) for orders of 1,500 or more. What is the best ordering policy?