Removing file permissions in Linux

Question:
What command removes the write permission for the group from a file?

1. chmod g=w some_file
2. +chmod g-w some_file
3. chmod w-g some_file
4. chmod w=g some_file

Answer:
B - is the correct answer. The chmod g-w some_file command can be used to remove write permission for the group from some_file file