Removing bulbs

This task is about electric circuits.
 
Why is it important to know this? Every day we use electricity for such things as heating, lighting and cooking. Knowing what may stop an electrical circuit working is useful for working out why an appliance is not working, or to build electric circuits ourselves.
electric circuit
A box has four bulbs screwed into sockets on its top. A circuit diagram of this is drawn above.

Question

a)  When Bulb A is removed, all the bulbs go out.
     Which is the Bulb A socket?

    • 1

    • 2

    • 3

    • 4

Question

b)  When Bulb B is removed, no other bulbs go out.
     Which is the Bulb B socket?

    • 1

    • 2

    • 3

    • 4

Question

c)  If the bulb in Socket 2 is removed, what will happen?

    • Nothing; the remaining 3 bulbs will light up.

    • Only the bulbs in Sockets 3 and 4 will light up.

    • Only the bulbs in Sockets 1 and 4 will light up.

    • None of the bulbs will light up.