how to correct the error

Question

using System;
namespace classanotherclass {
  class Program {
    public class class1 {
      public int price {
        get;
        set;
      }
      public string productname {
        get;
        set;
      }
      public class1(int price, string productname) {
        this.price = price;
        this.productname = productname;
      }
      public int price1() {
        return price;
      }
    }
    public class class2: class1 {
      public class1 c;
      public int quantity = 80;
      public class2(): base(10, "rice") {}
      public int price2(class1 c) {
        return c.price * quantity;
      }
    }
    static void Main(string[] args) {
      var C = new class2();
      var p = C.price2();
      Console.WriteLine("total for rice" + p);
    }
  }
}