In the 'Tesla Motors' case, which one is not true?

$(-)$ Tesla brought a large part of its parts production in$-$house, making e$.$g$.90\%$ of Model S$-$specific plastic parts on its injection molding machines, which was unusual for a plant with low volume, and manufacturing its complete powertrain in$-$house.

Because the battery is the most expensive, heaviest, and most challenging component of an EV$,$ Tesla developed Lithium$-$lon batteries by itself.

Tesla designed the Model $S$ completely in$-$house, at a cost of about $$0\mathrm{.}5$ billion.

Instead of independent dealerships like other car manufacturers, Tesla built a network of company$-$owned stores with salespeople on salary rather than on commission.