( A ) 10 litres ammonia, 25 litres nitrogen, 15 litres hydrogen
( B ) 20 litres ammonia, 25 litres nitrogen, 15 litres hydrogen
( C ) 20 litres ammonia, 20 litres nitrogen, 20 litres hydrogen
( D ) 20 litres ammonia, 10 litres nitrogen, 30 litres hydrogen