答案选B.the larger
一般来说,形容词比较级做表语时前面不加任何冠词,但在下列情况下应加冠词.
①当形容词比较级修饰可数名词做定语时,通常前面加不定冠词.如：This coat is a bit longer.Could you show me a shorter one?
②当形容词比较级表示两者之间较为突出者时,前面常加定冠词．如：This is the better of the two books.Canada is the larger of the two countries.
③the more...,the more...句式,表示“愈……就愈……”．如：The more carefully you study,the fewer mistakes you’ll make.