The correct spelling is **surveillance**, which means close observation, especially of a suspected spy or criminal. The key identifier here is the double 'l' followed by a single 'i' before the 'a' and 'nce' ending. Options A, B, and C all have incorrect internal vowel or consonant placements (e.g., 'Surveilance' misses an 'l', 'surveillence' has the wrong vowel order).
