What is the lowest combined mpg in the US for the A6 transmission, a CO2 g/km under 303, engine capacity over 2461, and L/100km urban (cold) of 15.9?
SELECT MIN mpg-US Combined FROM table WHERE Transmission = a6 AND CO 2 g/km < 303 AND Engine Capacity > 2461 AND L/100km Urban (Cold) = 15.9