Which of the following is NOT a limitation on partnership losses deductible on a partner's personal income tax return?

The reasoning behind choosing the first option as the correct answer lies in understanding the nature of partnership loss deductions and the specific limitations imposed by tax regulations.

Section 263(A) refers to the capitalization requirement under IRS regulations, which addresses the treatment of certain expenses, requiring that rather than being deducted immediately, certain preproductive expenses must be capitalized and thus are not deducted as losses. However, the share of those expenses taken by a partner does not impose a limit on partnership losses that can be deducted against the partner's personal income.

In contrast, the other options represent clear restrictions established by tax law regarding when a partner can deduct losses. Specifically, the second option relates to the adjusted basis limitation, which specifies that a partner can only deduct losses up to their basis in the partnership interest. The third option identifies the at-risk limitation, meaning a partner can only deduct losses they are financially liable for. Lastly, the fourth option highlights that certain losses related to rental activities are treated separately, potentially subject to passive loss limitations for individual partners.

Thus, the first option stands out as it is not a direct limitation on losses deductible on a partner's personal income tax return, making it the correct response in this context.