The correct option is B 42
Given letters S,S,E,E,R,I
There are 4 distinct letters S,E,R,I.
We need to form 3-lettered words.
Case 1: All 3 letters are distinct.
Choosing 3 letters =4C3
Rearrangements =3!
Total =4C3×3!=24
Case 2: 2 are of one kind, 1 is different.
There are choices for repeated letters (S,E)=2C1
We need to choose 1 from remaining 3 letters =3C1
These can be rearranged in 3!2! ways.
Total =2×3×3=18
∴ Required words =24+18=42
Hence, the answer is 42.