Which of the following commands will find the string foo in the file filel M, regardless of foo being in
upper or lower case letters?

A.
catfilel.txt| grep-ifoo

B.
cat file 1.txt > grep-n foo

C.
grep-i foo | file 1 .txt

D.
grep-nfilel.txt<foo

E.
grep-nfoofile1.txt