Internal Battery Resistance: Two Light Bulbs, B₁ and B₂, Are

Internal battery resistance: Two light bulbs, B₁ and B₂, are connected to a battery having appreciable internal resistance as shown in the figure. What happens to the brightness of bulb B₁ when we close the switch S?

A) The brightness of B₁ increases permanently.
B) The brightness of B₁ decreases permanently.
C) The brightness of B₁ does not change.
D) The brightness of B₁ increases temporarily but gradually decreases back to its original brightness.
E) The brightness of B₁ decreases temporarily but gradually increases back to its original brightness.