CREATE TABLE table_56272 ("Driver" TEXT, "Entrant" TEXT, "Constructor" TEXT, "Chassis" TEXT, "Engine" TEXT, "Tyre" TEXT)

what is the engine when the tyre is d, the constructor is era and the driver is bob gerard?
SELECT "Engine" FROM table_56272 WHERE "Tyre" = 'd' AND "Constructor" = 'era' AND "Driver" = 'bob gerard'
SELECT "Engine" FROM "table_56272" WHERE "Constructor" = 'era' AND "Driver" = 'bob gerard' AND "Tyre" = 'd'