Each of Three Identical Electric Heaters Is Rated at 1000

Each of three identical electric heaters is rated at 1000 W when operated individually across 100-V lines. When the three are connected in series across a 120-V line, at what rate is electric energy converted to heat energy? Neglect variation of resistance with temperature.)

A) 0.48 kW
B) 1.0 kW
C) 1.2 kW
D) 3.0 kW
E) 3.6 kW