CAT 2015 Quantitative Ability

Check the options.
Option (a): If the product of the digits is 6. then the factors of 6 are 1,2,3 and 6. There is no combination of digits which satisfies the given conditions. So it is not the answer.
Option (b): If the product of the digits is 8, then the factors of 8 are 1. 2, 4 and 8. So only possible combination is 1,1, 2,4.
Hence, the number is 4112.
Similarly, we can check options (c) and (d).