n-type semiconductor has a large number of electrons. Yet it is electrically neutral. How ?

The total number of protons equals the total number of electrons.

The correct answer is Option 3: The total number of protons equals the total number of electrons.

An n-type semiconductor is electrically neutral because it is created by adding neutral pentavalent impurity atoms (like Phosphorus) to a neutral base crystal (like Silicon). Although these impurity atoms provide "free" electrons for conduction, for every free electron produced, a fixed positive donor ion is left behind in the crystal lattice. Since the total number of protons in the nuclei of all atoms remains exactly equal to the total number of electrons in the system, the net charge remains zero. Thus, the material as a whole remains electrically neutral.