I'm preparing for an exam and I got stuck on this question.
I understand that the alpha values 'affects' how much influence corresponding data point has on the position of the decision boundary, and that the alphas are between 0 and C=4 in this case.
Therefore, since point b) is closest to the decision boundary it makes sense that it should have alpha = 4. But I don't understand what they mean in the given solution when they say that "since the point is within the margin, slack is used here, hence, alpha = C = 4"
Is the slack value C always equal to the alpha value for points within the margin? Or is it only true in this case?