Which of the following commands makes /bin/foo executable by everyone but writable only by its owner?

A.
chmod o+rwx.a+rx/bin/foo

B.
chown 557 /bin/foo

C.
chmod 755/bin/foo

D.
chmod 557 /bin/foo

Explanation:
chmod 755 ecuals xxx x-x x-x meaning rwx, rx, rx.