In a certain code language, 'RISK' is coded as '3921' and 'KIRT' is coded as '1693'. How is 'S' coded in the given language?

To find the code for the letter 'S', let us analyze the given coded words step-by-step:

1. We are given that 'RISK' is coded as '3921'.
2. We are also given that 'KIRT' is coded as '1693'.

Let us compare the common letters and their corresponding digits between the two words:

The letters common to both 'RISK' and 'KIRT' are 'R', 'I', and 'K'.
The digits common to both codes '3921' and '1693' are '1', '3', and '9'.

Thus, the set of letters {R, I, K} corresponds to the set of digits {1, 3, 9} in some order.

Now, looking at the word 'RISK' (coded as '3921'):
The remaining letter in 'RISK' that is not common to both words is 'S'.
The remaining digit in the code '3921' that is not present in '1693' is '2'.

Therefore, the code for the letter 'S' must be 2.

The correct answer is Option 3 (2).