In a gas-liquid shell and tube heat exchanger, the_________________?

A. Presence of a non-condensable gas decreases the condensing film co-efficient
B. Gases under high pressure are routed through the tube side, because high pressure gases are
corrosive in nature
C. Gases to be heated/cooled is normally routed through the shell side, because the corrosion
caused by the cooling water or steam condensate remain localised to the tubes
D. All A, B. & C.