Answer:
Resistor B when individually connected and Resistor A when connected in series.
Explanation:
Suppose Resistor B has resistance R then resistor A has resistance 2R.
When individually connected across a given potential difference Resistor B will dissipate more power because power is inversely proportional to resistance.
While when connected in series across the same potential resistor A will dissipate more power because resistor A will have more voltage and power is directly proportional to the square of the voltage.