Large, medium and small ships are used to bring water. 4 large ships carry as much water as 7 small ships, 3 medium ships carry the same amount of water as 2 large ships and 1 small ship. 15 large, 7 medium and 14 small ships, each made 36 journey and brought certain quantity of water. In how many journey would 12 large, 14 medium and 21 small ships bring the same quantity? `25` b. `29` c. `32` d. `49`