At a temperature of $500 \ K$,the intrinsic electron number density $(n_e)$ and hole number density $(n_h)$ in a pure semiconductor are equal to $1.5 \times 10^{16} \ m^{-3}$. Now,by adding indium impurity,the hole density $(n_h)$ increases to $4.5 \times 10^{22} \ m^{-3}$. This doped semiconductor is:

• A
  a $P$-type semiconductor,in which the electron number density $n_e = 5 \times 10^9 \ m^{-3}$.
• B
  an $N$-type semiconductor,in which the electron number density $n_e = 5 \times 10^{22} \ m^{-3}$.
• C
  a $P$-type semiconductor,in which the electron number density $n_e = 2.5 \times 10^{10} \ m^{-3}$.
• D
  an $N$-type semiconductor,in which the electron number density $n_e = 2.5 \times 10^{23} \ m^{-3}$.