In which of the following file modes, the existing data of file will not be lost ?

1. 'rb'
2. ab
3. w
4. w + b
5. 'a + b'
6. wb
7. wb+
8. w+
9. r+

'rb', ab, a + b, r+

Reason —

1. 'rb' — This mode opens the file for reading in binary mode. It will not erase the existing data and allows reading of the file.
2. 'ab' — This mode opens the file for appending in binary mode. It will not erase the existing data but will append new data to the end of the file.
3. 'a + b' — This mode opens the file for reading and appending. It will not erase the existing data and allows both reading from and appending to the file.
4. 'r+' — This mode opens the file for reading and writing. It will not erase the existing data and allows both reading from and writing to the file.