Which one of the figures gives the temperatures dependance of density of water correctly?

An experiment takes 10 minutes to raise temperature of water from 0$$^\circ$$C to 100$$^\circ$$C and another 55 minutes to convert it totally into steam by a stabilized heater. The latent heat of vaporization comes out to be

At what temperature will the rms speed of air molecules be double that of NTP?

When the room temperature becomes equal to the dew point, the relative humidity of the room is