In retained profits are taxed twice.
a. proprietorships and partnerships
b. partnerships, proprietorships, and corporations
c. corporations
d. partnerships and corporations

C. corporations

Explanation:

Double taxation refers to when retained earnings are taxed twice. First retained earnings are taxed by company income tax. When the retained earnings are distributed owners still have to pay personal income tax

answer; ///(d); determining who competes most closely   with whom evaluating whether industry driving forces and competitive pressure favor some strategic groups and hurt others, and ascertaining whether the profit potential of different strategic groups varies due to the strengths and weaknesses in each groups respective market positions;