The following table provides the resistivity of three samples:

Sample	$A$	$B$	$C$
Resistivity	$1.6 \times 10^{-8} \Omega \cdot m$	$5.2 \times 10^{-8} \Omega \cdot m$	$100 \times 10^{-6} \Omega \cdot m$

Which of them is suitable for heating elements of electrical appliances and why?

(C) Sample $C$ is suitable for heating elements of electrical appliances.
Reason: Heating elements require materials with high resistivity so that they can produce a significant amount of heat when an electric current passes through them, according to Joule's Law of heating $(H = I^2Rt)$. Among the given samples, Sample $C$ has the highest resistivity $(100 \times 10^{-6} \Omega \cdot m)$, making it the most efficient choice for generating heat.