A resistor has a resistance of 8Ω at room temperature and is connected to a 12V supply. When it heats up, its resistance rises to 10Ω, and simultaneously the applied voltage is increased to 18V. Under these new conditions, the electrical power dissipated by the resistor
a) increases by 50%
b) decreases by 20%
c) increases by 80%
d) increases by 20%