Which of the following is NOT negotiable during contract discussions?

Pension benefits are typically defined by existing federal laws, state regulations, and established union contracts, making them less flexible for negotiation during contract discussions. These benefits are often set in stone due to their structured nature and legal frameworks, which aim to protect the rights of employees and ensure financial solvency for the pension plans. Unlike other elements such as hours of employment, terms and conditions, or vacation time, which can usually be adjusted through negotiations, pension benefits involve complex calculations and legal constraints that preclude straightforward negotiation. Thus, because of the definitive nature of pension benefits, they are seen as the aspect that is not negotiable during contract discussions.