The Number Density N of Conductions Electrons, the Resistivity $\rho$ , and the Temperature Coefficient of Resistivity

The number density n of conductions electrons, the resistivity $\rho$ , and the temperature coefficient of resistivity $\infty$ are given below for five materials. Which is a semiconductor?

A) n = 10²⁹ m^-3, $\rho$ = 10^-8 $\Omega$ . m, $\infty$ = +10^-3 K^-1
B) n = 10²⁸ m^-3, $\rho$ = 10^-9 $\Omega$ . m, $\infty$ = -10^-3 K^-1
C) n = 10²⁸ m^-3, $\rho$ = 10^-9 $\Omega$ . m, $\infty$ = +10^-3 K^-1
D) n = 10¹⁵ m^-3, $\rho$ = 10³ $\Omega$ .m, $\infty$ = -10^-2 K^-1
E) n = 10²² m^-3, $\rho$ = 10^-7 $\Omega$ .m, $\infty$ = +10^-3 K^-1