Which switch in the circuit when closed will produce short-circuiting?

A. A
B. B
C. C
D. None of the above

Hint: To answer this question, we must have a concept of when there is a short circuiting. As we know that short circuiting will happen when both the positive and negative terminal will enter the cell without any resistance. And according to this we can easily figure out which option is the correct option.

Complete step by step answer:
The circuit diagram,

We can see that when switch B is closed the circuit becomes complete with the resistance and same goes with the switch C as it connects with the lamp and the circuit gets complete and here only switch A is closed, we can see there is no resistance and short circuit happens.
Here in the above question to prevent the short circuiting we must add any resistance or bulb or any electric appliances to avoid the short circuiting.
And for short circuiting there are many causes such as loose connection and in modern era we use a device called MCB miniature circuit breaker to prevent the connection to short circuit.
These are the devices which sense the large amount of current or overloading and break the circuit to avoid the problem.
Hence, we can say that option (A) is the correct option.

Note: A short circuit is a low-resistance connection between two conductors that supply electrical power to a circuit. The power source or cell can damage after the short circuiting as it causes a lot of excessive current flow. If a fuse is present in the supply circuit, it will blow, opening the circuit and interrupting current flow.