The correct answer is species
Following Aufbau rule and Hund principle, the order of filling of the orbitals is this:

So, the first, second, and fourth option are not correct.
The third option does meet the filling order.
Answer:
I would say there is 10 (2 in the ethyl group, 3 in the three methyl groups and 5 in the pent chain)
Geothermal energy is the thermal energy generated and stored in the Earth. Thermal energy is the energy that determines the temperature of matter. The geothermal energy of the Earth's crust originates from the original formation of the planet and from radioactive decay of materials