单选题：In our experiment of adding a new file system, we use the follow

In our experiment of adding a new file system, we use the following scripts to test our new file system.
```
1. dd if=/dev/zero of=myfs bs=2M count=1
2. /sbin/mkfs.ext2 myfs
3. ./changeMN myfs
4. mount –t myext2 –o loop ./fs.new /mnt
5. mount
6. umount /mnt
7. mount –t ext2 –o loop ./fs.new /mnt
```
The code in line 7 will cause an error, but why?@[D](1)
A. incorrect usage of mount
B. the two file systems have different super blocks
C. the two file systems have different inode structures
D. the two file systems have different magic numbers





A.incorrect usage of mount
B.the two file systems have different super blocks
C.the two file systems have different inode structures
D.the two file systems have different magic numbers


答案：D