a
\(\vec{E}=-\bar{\nabla} V\)

where \(\bar{\nabla}=\hat{i} \frac{\partial}{\partial x}+\hat{j} \frac{\partial}{\partial y}+\hat{k} \frac{\partial}{\partial z}\)

\(\therefore \quad \vec{E}=-\left[\hat{i} \frac{\partial V}{\partial x}+\hat{j} \frac{\partial V}{\partial y}+\hat{k} \frac{\partial V}{\partial z}\right]\)

Here, \(V=4 x^{2} \quad \therefore \quad \vec{E}=-8 x \hat{i}\)

The electric field at point \((1,0,2)\) is

\(\vec{E}_{(1,0,2)}=-8 \hat{i}\,Vm^{-1}\)

So electric field is along the negative \(X\) -axis.