Choice "c" is correct. A C corporation (a regular corporation) must pay federal income tax. A C corporation is not a pass-through entity like the other entities listed.

Choice "b" is incorrect. A general partnership is a pass-through entity and does not pay federal income tax.

Choice "d" is incorrect. A limited partnership is a pass-through entity and does not pay federal income tax.

Choice "a" is incorrect. A joint venture is a pass-through entity (a joint venture is similar to and is treated as a partnership) and does not pay federal income tax. A joint venture is a combination of two or more (tax) persons who jointly seek a profit from some business venture without designating themselves as an actual partnership or corporation.