Which of the following commands finds all lines in the file operating-systems.txt which contain the term linux, regardless of the case?
A . igrep linux operating-systems.txt
B . less -i linux operating-systems.txt
C . grep -i linux operating-systems.txt
D . cut linux operating-systems.txt
E . cut [Ll] [Ii] [Nn] [Uu] [Xx] operating-systems.txt
Answer: C