In a certain code language, the word "DONKEY" is written as "YEKNOD". Using the same code rule, how is the word "RAINBOW" written in that language?

Introduction:
This is a straightforward coding and decoding question based on reversing the order of letters in a word. The code for "DONKEY" is given as "YEKNOD", and we must apply the same transformation to the word "RAINBOW". Problems like this test your ability to spot simple structural patterns rather than complicated substitutions.

Given Data / Assumptions:
We are told that DONKEY becomes YEKNOD. There is no indication of any letter substitutions or shifts, only an apparent rearrangement. We assume that every word is encoded by reversing its sequence of letters, with no extra changes to individual characters.

Concept / Approach:
The first step is to observe how DONKEY and YEKNOD relate. If we write DONKEY forwards and YEKNOD underneath, we can immediately see that YEKNOD is simply DONKEY written backwards. Once this is clear, we adopt the rule "reverse the letters of the word" and apply it to the new word RAINBOW.

Step-by-Step Solution:
Step 1: Write the word DONKEY and compare it to YEKNOD. The letters are D O N K E Y and Y E K N O D, which are in exactly opposite order.Step 2: Conclude that the coding rule is to reverse the word, placing the last letter first, the second last letter second, and so on.Step 3: Now apply this rule to the word RAINBOW. The letters of RAINBOW in order are R, A, I, N, B, O, W.Step 4: Reverse this order. Starting from the end, we get W, O, B, N, I, A, R.Step 5: The reversed sequence gives the coded form WOBNIAR.

Verification / Alternative check:
If we again reverse WOBNIAR, we should return to the original word RAINBOW. Reading WOBNIAR from right to left yields R, A, I, N, B, O, W, which confirms that our transformation is simply a reversal and that it has been applied correctly.

Why Other Options Are Wrong:
The option WOBNAIR misplaces the letters A and I, which means it is not a pure reversal of RAINBOW. The option WONBAIR rearranges letters in a different pattern and does not match the simple reverse rule observed with DONKEY. The option WOBNRAI incorrectly orders the last three letters. The option WOBINAR also fails to keep the correct reversed sequence of the middle letters.

Common Pitfalls:
Students sometimes reverse only part of the word or accidentally swap the positions of letters in the middle. It can help to write the word in a column and then write the reversed sequence directly underneath to avoid mistakes.

Final Answer:
The word "RAINBOW" is written as WOBNIAR in the given code language.