单选题：若fp1 = open("test.txt","r")

若fp1 = open("test.txt","r")
以下哪个读取文件的方式line返回的不是字符串？（）



A.for line in fp1
B.line = fp1.read()
C.line = fp1.readline()
D.line = fp1.readlines()


答案：D