Final answer:
While Victor's exam and certification costs aren't categorized as a tax, his future earnings as a self-employed plumber or as a business owner would be subject to individual income tax, corporate income tax (if applicable), and payroll tax on salaries.
Step-by-step explanation:
The type of tax Victor must pay for his plumbing certification exam is not directly indicated by a specific tax category such as corporate income tax, individual income tax, or payroll tax. These are types of federal taxes that would be applied to profits, salary, and wages, respectively. Since Victor is paying for a certification exam, this may be considered a personal expense or an investment in his professional development, which doesn't typically fall under a tax payment category. However, once he starts working, any profits made through self-employment or from his own plumbing business would be subject to individual income and potentially corporate income tax if incorporated. Additionally, if he pays himself a salary, he would have to handle payroll taxes as well.