Implement extension Method C#

I need to implement this method :Reflectable reflect<T>(IEnumerable<T> src) but i'm having troubles to get the expected output. Hope someone can help me thanks.

Here the interface Reflectable:

interface Reflectable : IEnumerable<string> { Reflectable Prop(string propName);}

and the expected Output:

IEnumerable<Student> stds = //Students
IEnumerable<String> r1 = reflect(stds).Prop("Id"); 
IEnumerable<String> r2 = reflect(stds).Prop("Name").Prop("Id").Prop("Age"); 
IEnumerable<String> r3 = reflect(stds);
r1.ToList().ForEach(Console.Write); // {3213}{3124}{35454}... 
r2.ToList().ForEach(Console.Write); // {Jose, 3213, 89}{Maria, 3124, 34}{Prominencia, 35454, 23}... 
r3.ToList().ForEach(Console.Write); // {}{}{}...