Indian Institute of Foreign Trade 2010 Solved Paper

We can see that letters are S, S, E, E, I, R.
Case 1: When all 4 letters are different. There is only one way where we select one each S, E, I, R.
Total number of 4 letter words which can be formed using these letters $=4!=24$
Case 2: When all 2 letters are of 1 type and 2 letters are different.
Total number of ways in which 4 letter can be chosen $=2\mathit{C}1\times 3\mathit{C}2=6$
Total number of 4 letter words which can be formed using these letters$=6\times \frac{4!}{2!}=72$
Case 3: When all 2 letters are of 1 type and remaining 2 letters are of different another same type. There is only one way when we select S, S, E, E.
Total number of 4 letter words which can be formed using these letters$=\frac{4!}{2!\times 2!=6}$
We have considered all possible cases. Hence, total number of four letters of the word can be made $=24+72+6=102$
Hence, option D is the correctanswer.