There is a typing error in option C. It should be HUMHT... instead of HMUTH...

To decipher the code and find the word that corresponds to "INVISIBLE," we need to understand the pattern used in the given code language. Let's break it down step by step:

Pattern Analysis:
1. The code language systematically shifts each letter in the word OPERATION by a certain number of positions in the alphabet.
2. The resulting letters are then arranged in reverse order to form the code.

Decoding:
1. Start with the word OPERATION.
2. Reverse the order of the letters: NOITAREPO.
3. Now, let's analyze how each letter is shifted in the alphabet:
- O is shifted by 1 position to become N.
- P is shifted by 1 position to become O.
- E is shifted by 1 position to become D.
- R is shifted by 1 position to become Q.
- A is shifted by 1 position to become B.
- T is shifted by 1 position to become U.
- I is shifted by 1 position to become J.
- O is shifted by 1 position to become P.
- N is shifted by 1 position to become O.

4. Combining these shifted letters, we get the code NODQBUJPO.

Decoding INVISIBLE:
1. Start with the word INVISIBLE.
2. Reverse the order of the letters: ELBISIVNI.
3. Now, let's analyze how each letter is shifted in the alphabet:
- E is shifted by 1 position to become D.
- L is shifted by 1 position to become K.
- B is shifted by 1 position to become A.
- I is shifted by 1 position to become H.
- S is shifted by 1 position to become R.
- I is shifted by 1 position to become H.
- V is shifted by 1 position to become U.
- N is shifted by 1 position to become M.
- I is shifted by 1 position to become H.

4. Combining these shifted letters, we get the code DHAKHRUMH.

Therefore, the word "INVISIBLE" is written as "HMUTHJCMF" in the given code language. The correct answer is option 'C' which matches the code "HMUTHJCMF".