Electric Current and Its Effects

Which of the following precautions need not be taken while
using electric gadgets/appliances/circuit?
(a) We should never touch a lighted electric bulb connected
to the mains.
(b) We should never experiment with the electric supply from
the mains or a generator or an inverter
(c) We should never use just any wire or strip of metal in
place of a fuse.
(d) We should never turn the switch in ON position.