Explanation:

- In the code language, LUCKNOW is written as 6. Notice that LUCKNOW has 7 letters. So the code might be one less than the number of letters.

- PATANA is written as 5, and it has 6 letters. Again, the code 5 is one less than the number of letters.

- It seems the rule is to subtract 1 from the total number of letters in the word.

- RAJASTHAN has 9 letters. Subtracting 1 gives us 8.

- Therefore, RAJASTHAN will be written as 8 in this code language. Hence, the correct option is:

- Option 1: 8

.