The command used to grant execute permission to the group for a file named "script.sh" in Linux is: chmod g+x script.sh

Explanation of the options provided:

• chmod g+x script.sh: Grants execute (+x) permission to the group (g) for the file script.sh.
• chmod u+x script.sh: Grants execute permission to the owner (u) of the file script.sh.
• chmod o+x script.sh: Grants execute permission to others (o or everyone else) for the file script.sh.
• chmod a+x script.sh: Grants execute permission to all (a, which stands for owner, group, and others) for the file script.sh.