Father says to his son: “On the date of birth of yours, I was twice older than you are now.” Then which one of the following statements is true? 

(a) The present ages of the father and his son are 30 years and 10 years respectively. 

(b) The present ages of the father and his son are 48 years and 12 years respectively. 

(c) Nothing can be said about their ages. 

(d) The ratio of the present ages of the father to the son is 3 : 1.