In which type of boiler do the gases of combustion pass through tubes surrounded by...

In a fire tube boiler, hot gases of combustion pass through tubes, and water surrounds those tubes, absorbing the heat to create steam or hot water.

Correct: Fire tube (B) – Gases inside tubes, water outside.

Incorrect:

A. Water tube – The reverse: water flows inside the tubes, combustion gases surround them.

C. Vertical tube – Refers to orientation but still a water-tube or fire-tube design.

D. Cast iron sectional – Built from joined cast iron sections, not tubular gas-through-water design.