Here A option is wrong because 6 means read and write permission are allowed only not execute permission.
For groups read and execute permission are allowed so option c is also wrong.
So answer should be B.
(Sat, Apr 30, 2011 01:04:02 AM)
0 --- 000 All types of access are denied
1 --x 001 Execute access is allowed only
2 -w- 010 Write access is allowed only
3 -wx 011 Write and execute access are allowed
4 r-- 100 Read access is allowed only
5 r-x 101 Read and execute access are allowed
6 rw- 110 Read and write access are allowed
7 rwx 111 Everything is allowed
652 = -(rw-)(r-x)(-w-)
Therefore, the file has write permission (-w-) to others only valid from the given options.