If the average disposable income of families of a class is ₹ 20000 in the year 2013 and if the cost of living index number of that class for the year 2015 with the base year 2013 is 130, what should be the average disposable income of the families of this class in the year 2015?
(a) ₹ 26000
(b) ₹ 20130
(c) ₹ 20000
(d) ₹ 14000
