`B_(1), B_2 and B_3` are the three identical bulbs connected to a battery of steady emf with key `K` closed. What happens to the brightness of the bulbs `B_(1)` and `B_(2)` when the key is opened?
A. Brightness of the bulb `B_(1)` increases and that of `B_(2)` decreases
B. Brightness of the bulbs `B_(1)` and `B_(2)` increases
C. Brightness of the bulb `B_(1)` decreases and `B_(2)` increases
D. Brightness of the bulbs `B_(1)` and `B_(2)` decreases
