The Allegory of the Cave. The dialogue between Socrates and Glaucon is probably fictitious and composed by Plato; whether or not the allegory originated with Socrates, or if Plato is using his mentor as a stand-in for his own idea, is unclear. In the dialogue, Socrates asks Glaucon to imagine a cave, in which prisoners are kept.
The d sublevel consists of five orbitals that can hold a maximum of  two electrons each. The total maximum number of electrons that the  d sublevel can hold is 10 electrons.
The maximum number of electrons in each orbital of any kind is 2. s orbital can hold maximum of 2 electrons no matter what the number (principle quantum number like 2,3,4,5 is ) and d orbital has 5 subshells and each sub shell can hold 2 electrons. So altogether each d orbital can hold 10 electron.