Final answer:
The correct answer is option d. The part of the equation used to represent a signing bonus when modeling hourly pay is Additional compensation.
Step-by-step explanation:
Additional compensation is the part of the equation used to represent a signing bonus when modeling hourly pay. When calculating hourly pay, base salary (A) represents the fixed amount of money an employee earns per hour. Hourly rate (B) represents the amount paid for each hour worked. Variable pay (C) refers to any additional earnings tied to job performance or productivity, such as commissions or bonuses.
Additional compensation (D) encompasses any extra payments received by the employee, including signing bonuses.