In a water-tube boiler, the flue gas flows through the following accessories :
1. Super heater 2. ID fan
3. Air heater 4. Economizer
Which of the following gives, the correct sequences of the flue gas through these accessories:

A

1, 2, 3, 4

B

3, 1, 4, 2

C

1, 4, 3, 2

D

1, 3, 2, 4