The correct option is A In parallel
For the electric lamps connected with the mains to glow so that the switching on or off a lamp has no effect on other lamps, they should be connected in parallel circuit.
In a parallel connection, each bulb has its own path to the power supply. The electricity goes through each bulb only once. The current from the power source is shared between the two bulbs.
Components connected in parallel are connected so the same voltage is applied to each component. In a parallel circuit, the voltage across each of the components is the same, and the total current is the sum of the currents through each component. Hence correct option is A.