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

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

A.
chmod 557 /bin/foo

B.
chmod o +rwx,a+rx /bin/foo

C.
chown 557 /bin/foo

D.
chmod 755 /bin/foo

Explanation/Reference:
A) would set -wx-wxrwx permissions on /bin/foo
B) would set at least r-xr-xrwx on /bin/foo (depending on former permissions)
C) would set the UID of /bin/foo to 557 (even if no user exists with that id)