Femi takes $$2$$ hours and $$53$$ minutes to cycle from London to Reading. If he arrived at~ $$15:21$$, at what time must he have set off? 
选项为:A:$$12:24$$pm  B:$$1:24$$pm  C:$$12:28$$pm  D:$$12:18$$pm  E:$$1:28$$pm  请回答其中一个选项.