while和as引导原因状语从句的区别,有个问题_______footballisapopularballgameinthatcountry,thereisunbelieablynoregularleaguematch.A.WhenB.AsC.WhileD.Despite指导一下选B还是C?貌似答案是while,但As为什么不

　　while和as引导原因状语从句的区别,有个问题

　　_______footballisapopularballgameinthatcountry,thereisunbelieablynoregularleaguematch.

　　A.WhenB.AsC.WhileD.Despite指导一下选B还是C?貌似答案是while,但As为什么不行?

　　这句话到底是什么意思？这句是让步状语从句还是表原因？