A Charged Ring Having Radius $R$ And Total Charge $Q$ Is Lying in the X-Y Plane and Centered at the Is

Multiple Choice

A charged ring having radius $R$ and total charge $Q$ is lying in the x-y plane and centered at the origin. The expression for the electric field at $z \rightarrow \infty$ (in the z direction) is

A) $E _ { z } = 1 / \left( 4 \pi \varepsilon _ { 0 } \right) Q / z ^ { 2 }$
B) $E _ { z } = 1 / \left( 4 \pi \varepsilon _ { 0 } \right) Q / ( z + R ) ^ { 2 }$
C) $E _ { z } = 1 / \left( 4 \pi \varepsilon _ { 0 } \right) Q / ( z - R ) ^ { 2 }$
D) $E _ { z } = 1 / \left( 4 \pi \varepsilon _ { 0 } \right) Q R / z ^ { 3 }$