once there were 2 scientists travelling in a train from mumbai to delhi.one of them was a mathematician ,he had the habit of talking in mathematical terms.to overcome the boredom of the journey the second scientist asked him''how many children do you have?'' first scientist replied''i have 3 sons''.second scientist asked for their ages.1st scientist replied ''the product of their ages is 72 and the sum of their ages is equal to my house number'' 2nd scientist thought for a while and requesteed him to give one more hint as the information was not sufficient for guessing the correct ages of the 3 sons.1st scientist gives him the last clue that ''my eldest son has green eyes''.immediately ''the 2nd scientist'' could tell him his son's ages.what was the age of the eldest son? a)6 b)8 c)9 d)12