The for loop you've got there doesn't make much sense. The point of loops is to do the same task repeatedly, In your case the repetitive task is checking the answer against the expected result. This needs to be the body of the loop. Try something like this:
Dim answers = {RdAnswer1, RdAnswer2}
Dim expected = {"A", "A"}
Dim score As Integer = 0
For i As Integer = 0 To answers.Length - 1
If answers(i).SelectedValue = expected(i) Then
score += 1
End If
Next
We store answers and expected results as arrays. Then we loop trough them and if we find a match we update the score.