13. The term "double taxation" refers to which of the following? a. Corporations must pay income taxes on their net income, and their stockholders must b. in a partnership, both partners are required to claim their share of net income on their tax c. A sole proprietorship must pay income taxes on its net income and the owner is also d. A sole proprietorship must pay income taxes to both the state government and the pay income taxes on their dividends returns required to pay income taxes on withdrawals federal government