Correct Answer: IMPORTANT

Solution : Given:
IMPROVEMENT

Let's compare all the option words with the word IMPROVEMENT –
First option: ROPE; All the letters of ROPE are present in the word IMPROVEMENT.
Second option: TRIM; All the letters of TRIM are present in the word IMPROVEMENT.
Third option: IMPORTANT; Only one T is present in IMPROVEMENT but in IMPORTANT two T's are present. Also, A is not present in the word IMPROVEMENT. Therefore, all the letters of IMPORTANT are not present in the word IMPROVEMENT.
Fourth option: PROVE; All the letters of PROVE are present in the word IMPROVEMENT.

Only IMPORTANT cannot be formed from the word IMPROVEMENT. Hence, the third option is correct.