3. See the picture below, which numbers show the followings: optic never,optic chiasm, and olfactory bulbVIIIVIIXIIIIIIItrVIрIVIX XXI

The number from the picture that show the optic nerve, optic chiasm and olfactory bulb are:
Optic nerve = II
Optic chiasm = II (the center of the structure)
Olfactory bulb = I