下列说法正确的是：（单选） Which of the following statements is correct？ （There is only one correct answer）

A、空串就是空白串“Empty string” is blank string.

B、空串是任意字符串的子串 Empty string is a substring of arbitrary string.

C、串只可以采用顺序存储，不可以采用链式存储 String only can be stored in sequential method and cannot be stored in linked method.

D、在C++标准中，char S[M]最多能表示长度为M的字符串 In C ++ standards, char S[M] can represent up to a string of length M.