Assinale a alternativa CORRETA.

I. !$ \dfrac {100} {300} \, = \, \dfrac {1} {3} !$

II. !$ \dfrac {40} {80} \, = \, \dfrac {1} {2} !$

III. !$ \dfrac {100} {300} \, = \, \dfrac {2} {3} !$

IV. !$ \dfrac {100} {400} \, = \, \dfrac {1} {3} !$