What is the actual value of _grade?

What is the actual value of _grade?

public static void Main(string[] args) { lastScore;[] examScores = new []{ , , , , };lastScore = ;AddScore(lastScore, examScores);}public static void AddScore( _grade, [] _gradeArray) { totalOfScores = ; numExams = _gradeArray.Length;double finalGrade; ( i = ; i < numExams; i++) {totalOfScores = totalOfScores + _gradeArray[i];}totalOfScores += _grade;finalGrade = totalOfScores / (_gradeArray.Length + );finalGrade = Math.Round(finalGrade);Console.WriteLine("Your average the exams is .", finalGrade + ".");18}