For this question we want the find the residual like the question states. We know the observed value of x = 6 which is
(6, 4) and we know the predicted value of x = 6 which is
(6 , 3.44)
To find the residual we will do the observed value of y - predicted value of y
4 - 3.44 = 0.56 therefore the answer will be
C 0.56