Which of the following rational numbers is positive?
(a) \(-\dfrac{8}{7}\)
(b) \(\dfrac{19}{-13}\)
(c) \(\dfrac{-3}{-4}\)
(d) \(\dfrac{-21}{13}\)
A rational number is positive if numerator and denominator have the same sign. Here, \(\dfrac{-3}{-4} = \dfrac{3}{4} > 0\).