:Cell$-$Antenna International $($CAl$),$ a Japanese cellular antenna manufacturer has received a large order to manufacture and install cell phone antennas in the Iraqi city of Baghdad. Thecontract is valued at JPY $10$M and will be paid by the buyer in the currency of the contract. CAl does not have any strategic partners it can leverage to ensure a successful installation of theantennas. Although the country's political situation has raised significant concerns on the completion of the contract, the Executive Vice President signed this contract to help CAl diversifyits market reach.In every contract, CAl seeks a $25\%$ advance payment which is non$-$refundable in case the buyer cancels the contract soon after signature. While negotiating with the buyer, CAl had to removethe "non$-$refundable" clause. Which of the following could CAl request from the buyer to help warrant the advance payment it will need to pay?

A$)$ Letter of guaranteeB$)$ Documentary letter of credit at sightC$)$ Red clause letter of creditD$)$ Confirmed letter of guarantee