Java programmer has question about Generics

[xusword]

Hi all

I was a Java programmer, I am used to doing something as followed:

IO Example: (It's not the best example I can come up with, but it is the simplest one)

public interface IO<T>{
    T parse(stream s);
    String print(T o);
}

public class IOA extends IO<A>{
    A parse(stream s){
        A instanceA;
        // parse A
        return instanceA;
    }

    String print(A a){
         return a.toString();
    } 
}

public class IOB extends IO<B>{
    B parse(stream s){
        A instanceA;
        //parse B
        return instanceB;
    }


    String print(B b){
         return b.toString();
    } 
}

so far, everything can translate to C#
BUT
I cannot find a way to translate the following to C#

public class Peeker{

      public Parser<?> peekAndFindSuitableParser(stream s){

             // peeking.... then determine
             if (/* need to return parserA */...){
                   return new ParserA();
             }
             else if (/* need to return parserB */...){
                   return new ParserB();
             }

      }
}

Is it possible to translate this to C#?
If not, should I just remove all the generics in these code?