Given a class as follows:

```
public class Student
{
  public int Age { get; set; }
  public int Score { get; set; }

  public Student() {}
  public Student(int age, int score)
  {
     Age = age;
     Score = score;
  }
  ...

}

List<Student> listStd;

```

Question 1> How to sort Student first by score then by age in ascending order?

Question 2> How to find the Student with least score and then smallest age?

I know how to do all these in C++ and I want to know the alternative way in C#.