The circuit is working, and all three bulbs are lit. If a switch at A is opened, what will happen to the circuit?
A. All three bulbs will stay lit.
B. All three bulbs will go out.
C. Bulb 1 will go out, but bulbs 2 and 3 will remain lit.
D. Bulbs 1 and 2 will go out, but bulb 3 will remain lit.