For a given non zero value of m each of the lines \(\frac xa - \frac yb = m\) and \(\frac xa + \frac yb = m\) meets the hyperbola \(\frac{x^2}{a^2} - \frac{y^2}{b^2} =1\) at a point. Sum of the ordinates of these points, is
(a) \(\frac{a(1+m^2)}m\)
(b) \(\frac{a+b}{2m}\)
(c) \(\frac{b(1+m^2)}m\)
(d) 0