Please show me the output and how to test each

QUESTION 39 The Octal number to be given along with chmod command to make a file readable, writable and executable to the owner, readable and executable to group and others is: 000 755 744 555 None of the above QUESTION 40 What is a hidden file or directory? A file that doesn't have any write permissions A file that only allows permissions for the owner A file with a filename that begins with a. (dot) A file that is owned by the user, but which doesn't appear in any subdirectory of the user's home directory QUESTION 41 Which of the following commands will change the current directory to the parent directory of the current directory? cd cd. ca QUESTION 42 Which of the following Unix commands can be used to create an empty file in the current working directory? ef create touch cal QUESTION 43 Which command is used to set the executable permission to all of the files named "letter"? chmod ugotr letter chmod ugo+rw letter chmod u+x letter chmod ugo+x letter None of the above QUESTION 44 Which command is used to display the end of the file? head- tail eof bof None of the above