What do the permissions -rwSr-xr-x mean for a binary file when it is executed as a command?

What do the permissions -rwSr-xr-x mean for a binary file when it is executed as a
command?

A.
The command is SetUID and it will be executed with the effective rights of the owner.

B.
The command will be executed with the effective rights of the group instead of the owner.

C.
The execute flag is not set for the owner. Therefore the SetUID flag is ignored.

D.
The command will be executed with the effective rights of the owner and group.