Why helium is duplet ??

The outermost shell of helium for example is filled with only two electrons. Hydrogen and lithium become stable by acquiring the electronic configuration of the nearest inert gas, which is helium. This is the duplet (or duet) rule.

The answer should be c.

Firstly, the water in the dams hold gravitational potential energy as they are above ground level. the gravitational potential energy is then transferred to kinetic energy as it falls, spinning the turbinethe turbine then spins the generator, which is a large magnet surrounded by metal coils. by doing this, the generator generates electricity. in this action, the energy transfer taken place is kinetic to electric energy