1.I have a file data.txt which has list of all directory names

2.Now I want to grep every dir name in data.txt  with the contents of all the  *.c files in the cwd recursively .

3.Now report only those files and the matching lines whose grep is
case-sensitive meaning if we grep for "modem" in all the contents of *.c,any .c file which has a different case other than "modem",meaning Modem,moDEM etc,all such .c files need to be printed along with the matchingline