Choose the word which is the same in neaning as the word given in capital DARKinvisitefrighteninghauntingundiscussedchallenging

To find a synonym for the word "DARK," let's analyze the options provided:

1. Invisible: This means not able to be seen, which is not synonymous with "dark."
2. Frightening: This refers to something that causes fear, not directly related to "dark."
3. Haunting: This refers to something that remains in the mind or can also be eerie, but it's not a direct synonym for "dark."
4. Undiscussed: This means something that hasn’t been talked about, again not a direct correlation to "dark."
5. Challenging: This implies difficulty, which does not relate to the meaning of "dark."

Upon analyzing all the options, none of them directly mean "dark." However, "haunting" could potentially relate to the concept of "dark" in a more metaphorical sense, but it would not be a precise synonym.

Final Answer

None of the options provided are perfect synonyms for "DARK," but "haunting" can have a related connotation in certain contexts.