Answer: Toyota 4x4
Marty noticed a black Toyota 4x4 driven on the bed of a truck transporting for the Statler Dealership, in Hill Valley. You could tell the Toyota was a 1985 because it had a solid front axle, and EFI decals on the side. '85 was the last year for solid front, and the first for EFI. You may recall Marty's line from the film, "Check out that four by four! That's hot."
A note on the other possible selections: The BMW was owned by the McFly family in the "corrected" 1985, at the end of the first "Back to the Future", but Marty expressed no specific desire for having one. A Ferrari was never mentioned in the film, and the family sedan did not even exist in Marty's revised 1985.