A Thermometer Is Made Such That the Freezing Point of Water

A thermometer is made such that the freezing point of water is defined to be 60.0°H and the boiling point of water at sea level is defined to be 520°H. What is the Celsius temperature at 240°H?

A) -13.8°C
B) 34.6°C
C) 31.0°C
D) -7.8°C
E) 39.1°C