४. If potential (in volts) in a region is expressed as \( V(x, y, z)=6 x y-y+2 y z \), the electric field (in N/C) at point \( (1,1,0) \) is
(a) \( -(2 \hat{i}+3 \hat{j}+\hat{k}) \)
(b) \( -(6 \hat{i}+9 \hat{j}+\hat{k}) \)
(c) \( -(3 \hat{i}+5 \hat{j}+3 \hat{k}) \)
(d) \( -(6 \hat{i}+5 \hat{j}+2 \hat{k}) \)
(2015)
