Air in a Space Heating System Is Heated While Being

Air in a space heating system is heated while being humidified by steam injection. On the psychrometric chart, this process will appear as a line that is

A) horizontal to the right,
B) vertical upward,
C) diagonal upwards to the right (NE direction)
D) diagonal upwards to the left (NW direction)
E) diagonal downwards to the right (SE direction)