[单选题]Finally,()weareswitchingtoanewcoupon-basedsystem,wewillbediscontinuingtheuseofcustomerrewardcards.Reassurecustomersthattheycanredeempointsuntiltheendoftheyear.Explaintocustomersthatthecouponsystemwillprovidegreatersavings.Ifacustomerhasanyfurtherquestions,pleasereferhimorhertothemanageronduty.Thankyouforyourhardworkinrecentweeks.Sincerely,GregA.althoughB.unless A B so C D because