Directions: In the following sentence, four words, marked as A, B, C, and D, are given in bold, out of which one word may or may not be misspelt. Identify the misspelt word and mark it as your answer. If all the highlighted words are correctly spelt, mark "All are correctly spelt" as your answer.

His mischievious (A) grin betrayed (B) his innocent facade (C), hinting at the trouble he was about to stir up in the otherwise tranquil (D) neighbourhood.