Which of the following UNIX command can be used in symbolic mode to grant the following permissions to Name.txt file?Owner-Read, write and execute group-remove execute, Others-only read a. chmod -u-rwx, g-rw-xorw Name.txt b.chmod -ustw,g-w oerw Name.txt c. chmod -v=rwx, 9-xoar Name.txt d. chmod -ust, g-rw+x,o=rw Name.txt Which of the following UNIX command shows the first few lines of Name.txt file? a. tail b, head C. sort d. echo