A stock corporation is generally taxed in the same manner as which type of organization?

A stock corporation is taxed in a manner similar to a non-general professional partnership primarily due to the entity's structure and tax treatment. Both stock corporations and non-general professional partnerships are typically subject to corporate taxation, particularly regarding their profits and income.

In the case of a stock corporation, the entity itself is taxed on its earnings, which may lead to double taxation when dividends are distributed to shareholders. Non-general professional partnerships, while often not taxed at the entity level, can operate similarly in terms of reporting income and deductions, and certain types may elect to be taxed as corporations as well.

This taxation structure contrasts with entities like general professional partnerships, sole proprietorships, or cooperatives, which have different rules regarding income taxation. General professional partnerships usually pass through income to partners who report it on their individual tax returns. Sole proprietorships are taxed directly to the owner, and cooperatives have distinct taxation rules based on their operations and profit distribution.

Thus, the similarity in taxation between stock corporations and non-general professional partnerships primarily lies in the characteristics of corporate taxation and how income is treated, leading to the correct identification of the latter in the context of the question.