Correct Answer: Allure

Solution : The correct choice is the second option.

Explanation:
The most appropriate synonym for "captivate" is "allure". To captivate means to attract or hold the attention of someone, and "allure" similarly conveys the idea of attracting or enticing through charm or appeal.
The meanings of the other options are as follows:

• Study: To examine or investigate systematically.
• Envelope: To enclose or cover completely.
• Arrest: To stop or hinder the progress of.

Therefore, the correct answer is allure.