Which one of the following .is the correct path of water flow through various components of boiler of a modern thermal power plant?
a. Economizer – boiler drum – water walls – boiler drum – super heater – turbine
b. Economizer – boiler drum – water wall – super heater – turbine
c. Economizer – water walls – boiler drum – super heater – turbine
d. Economizer – water walls – super heater – turbine