Sending Parameter

[C# Programming]

Hi guys,
I am beginner and developing a test program.

this is the description:Calculate the total mark and final grade:
Labs Mark is an integer from 0 to 10;
Assignmnet1 mark is an integer from 0 to 20
Assignmnet2 mark is an integer from 0 to 20
Final exam Mark is an integer from 0 to 50

Student passes the unit if and only if
• (Labs Mark + Assignment1 Mark + Assignment2 Mark)>=25 and Final exam Mark >=25

There are five grades, which should calculate as below:
• F ? If the total mark is less than 40;
• MF? if (40= 25 && (Final >= 25));
}

public readonly string Grade()
{

}

public override string ToString()
{
return string.Format("Name:{0}\nSurname:{1}\nID:{2:D6}",
name, surname, studentID);
}


}

}



my problem is I don't know what should I write in this Part:

public readonly string Grade()
{

}

I appreciate if someone help me.