Which of the following is not necessary for a circuit to form?
a. A conducting wire
b. Source of current
c. Device to use electricity
d. Switch in the off position

Fareeha, the answer to your query is the option d i.e Switch in off position. When the switch is in off position, the circuit is open and current doesn't flow thus we don't need a switch off to form a circuit. But it is still needed if switch on is there. I mean if we need to switch it off, then we need it otherwise it is not mandatory to have a switch off in a simple circuit.