When two vectors A and B are represented by the two adjacent sides of a parallelogram taken from the same point, the resultant vector is represented by
(a) the diagonal joining the free (arrowhead) ends of A and B
(b) either of the two diagonals, depending on which is longer
(c) the diagonal passing through the common tail of A and B
(d) the diagonal drawn from the arrowhead of A to the tail of B