Suppose myFile is in your working directory. Specify the command(s) you would use to do the following:

Give everyone permission to read myFile; do not change any other privileges.

Permit the owner (you) and group members to read and write the file; remove all privileges from everyone else.

Remove writing privileges from everyone but the owner.

Give the owner and group members permission to execute myFile, while giving the owner sole permission to read and write the file.