A dilute aqueous solution is to be concentrated in an evaporator system. High pressure steam is available. Multiple effect evaporator system is employed, because

• A. total heat transfer area of all the effects is -less than that in a single effect evaporator system.
• B. total amount of vapor produced per Kg of feed steam in a multiple effect system is much higher than in a single effect.
• C. boiling point elevation in a single effect system is much higher than that in any effect in a multieffect system.
• D. heat transfer co-efficient in a single effect is much lower than that in any effect in a multieffect system.