下列代码实现了将一个文件的内容复制到另一个文件的功能。下划线处应填入的代码是()import java.io.*;public class test { public static void main(String[] args) { try { FileInputStream is = new FileInputStream("D:\\from.txt"); FileOutputStream os = new _______________("D:\\to.txt"); byte[] str = new ___________[1024]; while (is.available() > 0) { is.read(str, 0, 1024); os.write(str); } is.close(); os.close(); } catch (ArrayIndexOutOfBoundsException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } }}

A. FileOutputStream, byte
B. FileInputStream, byte
C. FileOutputStream, str
D. FileInputStream, str