Continuing the discussion from Error on the Database Location Page:
Now I just had a look onto the keyboard of my MacBook Pro and noted it has a key labeled alt but none labeled option. What do I do? 
I believe Apple played around with the Option function key labels – this support page shows the “alt” style – and created a little mess this way: the function of the key is Option but the label on the keyboard might be “alt” on not so recent Mac models.
Therefore Apple themselves use this notation:
“Option (or Alt) ⌥”