英語單選題求助No matter ___ busy he is ,he won't give up his hobby

題目：

英語單選題求助
No matter ___ busy he is ,he won't give up his hobby
a,what
b,how
c,who
選什麼了?爲什麼不選 A
"無論他有多忙" 這句話用英語怎麼說?

解答：

busy是形容詞,用副詞修飾,how是副詞,what和who是代詞
"無論他有多忙"就是你說的這句