written and listed by their owning user => 7 => umask 0 read and listed by their owning group => 5 => umask 2 not accessible at all for everyone else => 0 => umask 7 => umask 0027, answer is B

Answer is B. 0027

777 for directories 666 for files written and listed by their owning user => 7 read and listed by their owning group => 5 not accessible at all for everyone else => 0 777 - 750 = 027

i don't know why b

Answer is B. 0027 The leading '0' means we're specifying the umask in octal (base 8). The '2' in the first position subtracts write permissions for "others" (everyone else). The '7' in the second position subtracts read, write, and execute permissions for the group. The '2' in the third position subtracts write permission for the user.

B is the answer

I say B

B is correct

I think this schema would be more easy to get about umask https://en.wikipedia.org/wiki/Umask

B. 0027

B. 0027

IS correct

Agreed 0027

Agreed, answer is B. 0027.

Mask (Numeric Notation) 137 Allowed Permissions rw-r----- https://wintelguy.com/umask-calc.pl

https://www.cyberciti.biz/tips/understanding-linux-unix-umask-value-usage.html