the temperature difference of an evaporator coil is supposed to be 15 degrees F. you measure only 5 degrees F. all operating pressures check out normally and so does the superheat and subcooling. what is wrong?

a. the superheat measurement you took must be off

b. the ambient temperture is excessive

c. the humidit level is low

d. the humidity level is high

(please select best answer and comment if possible -- thanks!)