Some fruits and vegetables also conduct electricity. It is explained with the following example

(i) Cut a potato into two halves.
(ii) Insert the copper wires of a tester into it.
(iii) Keep it for an hour.
(iv)There appears a greenish blue spot on the potato around the wire.
(v) It is because the current produces a chemical effect on potato.
(vi) Hence, it is clear that vegetables conduct electricity

LEDs are light Emitting Diodes. They are used to check electric current. Even when a weak electric current flows through it, it glows. These are available in many colours such as red, green, yellow, blue and white. LED has two wires, one is longer and the other is shorter. Larger wire is connected with +ve terminal and -ve to the shorter terminal.

The ordinary water we get from the tap, river, lakes and ponds is not as pure as distilled water. It contains so many impurities in the form of the salts. These impurities make it good conductor of electricity. As distilled water is free from salt, it is unable to conduct electricity.

An electric current through a conducting solution causes chemical reactions. e.g., bubbles of a gas may be formed on the electrodes. Change of colour of solutions may occur. The reaction would depend on which solution and electrodes are used. 

Due to the heating effect of current, the filament of the bulb gets heated to a high temperature and it starts glowing. However, if the current passing through a circuit is too weak, the filament does not get heated sufficiently and it does not glow.

In electric cell, chemical energy is converted into electrical energy.

Distilled water is not a good conductor of electricity but adding common salt make it conducting.

Electroplating is most common industrial application of chemical effects of electric current.

Electroplating is done on the iron to prevent it from rust and corrosion and it is cheap.

As sea water contains more salt which increases conductivity. So, sea water is a good conductor of electricity.

Due to the presence of various salt solution in fruits and vegetables, they are able to conduct electricity to some extent.

Three liquids which can conduct electricity are.
(i) Tap water
(ii) Lemon juice (citric acid)
(iii) Vinegar (acetic acid).

As per the question, solution B is a better conductor.

Layer of zinc is coated over iron because zinc prevents it from rust and corrosion.

Since, wet hand acts as good conductor. So, we feel electric shock when we touch electrical appliance with wet hands.