Explanation:

- In the given code language, each word is associated with a different object.

- According to the code:

- Orange is called apple.

- Apple is called grapes.

- Grapes is called watermelon.

- Watermelon is called chikoo.

- Chikoo is called orange.

- The question asks which of the options is orange in color.

- In reality, "orange" refers to the fruit/color we know.

- In the code, what we call "orange" is actually named "chikoo."

- Therefore, the word representing an orange in this code is "chikoo."

- Among the options, watermelon is called chikoo.

Correct Answer: Option 4 - Watermelon