Correct Answer - Option 1 : r̂
Concept:
Let positive charge density is ρl
Given that charge lies along the z-axis, and we have calculated the electric field at any point p which lies in the x-y axis, not on the z-axis.
So the expression of the electric field is given by
E = (ρl × âr ) /(2π × ϵ × r)
Where âr is the unit vector in direction of r
From the above expression, it is clearly shown that it has the direction in r.