在C++中，如何使用std::ifstream和std::ofstream来实现一个只包含字母、数字、英文标点、换行和空格的文件的复制？

A.

std::ifstream src("source.txt");

std::ofstream dst("destination.txt");char buffer[1024];while (src.read(buffer, 1024)) {

dst.write(buffer, 1024);}

B.

std::ifstream src("source.txt");

std::ofstream dst("destination.txt");

std::string content = src.get();

dst << content;

C.

std::ifstream src("source.txt");

std::ofstream dst("destination.txt");

src >> dst;

D.

std::ifstream src("source.txt");

std::ofstream dst("destination.txt");

std::string src_line;while (src >> src_line) {

dst << src_line;}