Which of the following is not a potential reimbursable expense during TDY travel?

During TDY (Temporary Duty) travel, expenses are typically reimbursable if they are directly related to the mission and necessary for the completion of travel duties. Personal entertainment, however, does not fall under this category as it is considered a non-essential expenditure. Reimbursements are designed to cover costs directly associated with travel, such as hotel accommodations, meals, and transportation, all of which serve a specific purpose for the individual's work-related responsibilities. Personal entertainment is viewed as a personal choice and not essential to the travel objectives, thereby making it an expense that is not reimbursable during TDY trips.