________ difficulties they may come across, they will help one another to get over them．
A.HoweverB.WhateverC.WhicheverD.Since在线课程B
wh-ever引导从句时经常是名词性从句或让步状语从句，根据句意本句引导让步状语从句。whatever修饰名词，however修饰形容词或副词。故选择B项。