Choice "A" is correct. An S corporation can only have one class of stock outstanding. Common and preferred stock would constitute two classes of stock.
Choice "c" is incorrect. One class of stock with different voting rights is allowed for S corporations.
Choice "b" is incorrect. Individuals, estates, and certain trusts may be shareholders in an S corporation.
Choice "d" is incorrect. Grantor trusts, Section 678 trusts, qualified Subchapter S trusts (QSSTs), certain testamentary trusts, and voting trusts are allowed to be shareholders in an S corporation.
