CREATE TABLE table_17431 ("Model/Engine" TEXT, "Capacity" TEXT, "Cylinders/Valves" TEXT, "Power/rpm" TEXT, "Torque  ( Nm ) /rpm" TEXT)

How many capacities are possible for the 1.6 Duratec model/engine?
SELECT COUNT("Capacity") FROM table_17431 WHERE "Model/Engine" = '1.6 Duratec'
SELECT COUNT("Capacity") FROM "table_17431" WHERE "Model/Engine" = '1.6 Duratec'