dealer options are accessories and add-ons that the dealer "adds to the car after it is delivered from the factory, or specially installed in the factory upon order".
some dealers call them freebies, although in truth, buyer paid for them, somewhere in the price breakdown. "there is nothing free, in the auto industry."
manufacturers allow some room for this in the pricing of the car.
for example, "this here's our car. our dealer's price is xxx bucks. you sell it for our corporation's price-controlled price of 1 million bucks. you can add your choice of freebies onto it, hovering at the added cost (to you-the-dealer) of yyy bucks, but you should sell it for 1 million bucks".
if buyer wants accessories that are not in the freebies list, he will probably have to pay extra for them.
some manufacturers control the buyer's price of their cars, to prevent the market from becoming a cutthroat market.