KVPY SX SB Exam 2015 Question Paper

An urn contains marbles of four colours : red, white, blue and green. When four marbles are drawn without replacement, the following events are equally likely :
(1) the selection of four red marbles
(2) the selection of one white and three red marbles
(3) the selection of one white, one blue and two red marbles
(4) the selection of one marble of each colour
The smallest total number of marbles satisfying the given condition is