A Resistor Develops Heat at the Rate of 20 W

A resistor develops heat at the rate of 20 W when the potential difference across its ends is 30 V. The resistance of the resistor is approximately

A) 45 Ω.
B) 5.5 Ω.
C) 30 Ω.
D) 1.5 Ω.
E) 2 Ω.