Oldsmobile also introduced a 5.7L (350 cu-in, V8) Oldsmobile Diesel engine option on its Custom Cruiser, Delta 88 and 98 models in 1978 and a smaller 4.3L (260 cu-in, V8) displacement diesel on the 1979 Cutlass Salon and Cutlass Supreme/Cutlass Calais models. These were largely based on their gasoline engines but with heavier duty cast blocks, re-designed heads, fast glow plugs, and on the 5.7L, oversized cranks, main bearings, and wrist pins. There were several problems with these engines, including water and corrosion in the injectors (no water separator in the fuel line), paraffin clogging of fuel lines and filters in cold weather, reduced lubrication in the heads due to undersized oil galleys, head bolt failures, and the use of aluminum rockers and stanchions in the 4.3L V8 engines. While the 5.7L was also offered on various Buick, Cadillac, Chevrolet, GMC, and Pontiac models, it was eventually discontinued by all divisions in 1985.  4.3L V6 diesels were also offered between 1982 and 1985.
Question: How many models did Oldsmobile offer a 5.7L engine in in 1978?
Answer: 3