Correct Answer: ALERT

Solution : Given:
LEGALIZATION

Now, let's compare all the option words with the word LEGALIZATION –
First option: ALERT; All the letters of the word ALERT are not present in the word LEGALIZATION. R is not present in the word LEGALIZATION.
Second option: ALLEGATION; All the letters of the word ALLEGATION are present in the word LEGALIZATION.
Third option: GALLANT; All the letters of the word GALLANT are present in the word LEGALIZATION.
Fourth option: NATAL; All the letters of the word NATAL are present in the word LEGALIZATION.

Therefore, ALERT cannot be formed from the word LEGALIZATION. Hence, the first option is correct.