What is displayed in the MessageBox window if the following code is executed?

int grade = 72;
if (grade >=80) 
{
    MessageBox.Show("A"); 
}
else if (grade >=70) 
{ 
    MessageBox.Show("B"); 
}
else if (grade >=60) 
{ 
    MessageBox.Show("C"); 
}
else if (grade >=50) 
{ 
    MessageBox.Show("D"); 
}
else 
{ 
    MessageBox.Show("F"); 
}