When a resistor R is connected to a current source, it consumes a power of 18 W. When the same R is connected to a voltage source having the same magnitude as the current source, the power absorbed by R is 4.5 W. The magnitude of the current source and the value of R are

(A) √18A and 1Ω (B) 3A and 2Ω (C) 1A and 18Ω (D) 6A and 0.5Ω