the essential requirements of a heater element are------------------

a]high resistivity ,low melting point.b]low resistivity,low melting point.c]low conductivity,hogh melting point.d]low resistivity,high melting point.e]high resistivity,high melting point.

The correct answer is (e) High resistivity and High melting-point
 
The essential requirements of a heater element are:

1. High resistivity (or High-specific resistance)
The heating element must have high resistivity (or high-specific resistance) so that small length of wire is required to provide particular amount of heat into the heater because the resistivity and the length of the wire is related as,
 $R=\rho \frac{l}{A}$
where,
 $$\begin{gathered} R=Resis\tan ce of wire \\ \rho =resistivity \\ l=length of wire \\ A=Cross-sectional area of wire \end{gathered}$$

2. High-melting point
The heating element must have high-melting point so that it can withstand for high temperature and even a little raise in temperature will not damage the heating element of the heater.