Brand new apple keyboard but can't see "Use all F1, F2, etc. keys as standard function keys”
I bought a brand new apple keyboard with numeric keypad, and want to use the function keys for volume etc, but when I go to adjust the Function keys in system preferences as I had with my old keyboard, "Use all F1, F2, etc. keys as standard function keys” is not appearing at all. See pic. Any ideas why?
iMac 27", OS X 10.11