Three identical bulbs are connected as shown in figure : 

 

 

 

 

 

Each bulb dissipate a maximum power P. Assuming at least one of the bulbs is dissipating maximum power, then:

If i in the current in bulb $B_1$, then it will divide equally in bulbs $B_2$ and $B_3$. 

Option (c) is wrong, option (d) is correct.

Also $P=i^{2}R$. Bulb $B_1$ glows with maximum power

Power dissipated in bulbs $B_2$ or $B_3$ ,

$P^{\text{'}}={\left(\frac{i}{2}\right)}^{2}R=\frac{P}{4}.$

Thus total power $=P+\frac{P}{4}+\frac{P}{4}=\frac{3P}{2}$ .

Option (b) is correct, option (a) is wrong.