To find the coded word for "SCOOTER", we need to understand the pattern used to code the word "TRAIN" as "SQZHM". Let's analyze the given pattern step by step:

Pattern Analysis:
1. The first letter of the coded word corresponds to the first letter of the original word.
2. For the succeeding letters, the code is obtained by moving three positions forward in the English alphabet.
3. In case there is no corresponding letter three positions ahead, we take the letter three positions before.

Applying this pattern to the word "TRAIN":
- The first letter 'T' remains the same.
- The second letter 'R' moves three positions forward to 'U'.
- The third letter 'A' moves three positions forward to 'D'.
- The fourth letter 'I' moves three positions forward to 'L'.
- The fifth letter 'N' moves three positions forward to 'Q'.

Therefore, "TRAIN" is coded as "SQZHM".

Now let's find the coded word for "SCOOTER" using the same pattern:

- The first letter 'S' remains the same.
- The second letter 'C' moves three positions forward to 'F'.
- The third letter 'O' moves three positions forward to 'R'.
- The fourth letter 'O' moves three positions forward to 'R'.
- The fifth letter 'T' moves three positions forward to 'W'.
- The sixth letter 'E' moves three positions forward to 'H'.
- The seventh letter 'R' moves three positions forward to 'U'.

Therefore, "SCOOTER" is coded as "RBNNSDQ" (Option B).

Let's analyze the other options to understand why they are incorrect:

- Option A: "TDPPUFS" does not follow the given pattern.
- Option C: "RBNNSDS" changes the last letter 'R' of "SCOOTER" to 'S' instead of 'Q'.
- Option D: "RBPPUFS" changes the fifth letter 'T' of "SCOOTER" to 'P' instead of 'W'.

Therefore, the correct answer is Option B: "RBNNSDQ".

As the first one is SCOOTER and now the first alphabet of this word is S,R comes before S . next alphabet of the word is C ,B comes before C . continue this method to get answer by this we can get answer easily