问题如下：
Which of the following statements about participating preference shares is true?
选项：
A. Participating preference shares can be converted into common stock.
B. Participating preference shares can obtain voting rights.
C. Participating preference shares can receive extra dividends.
解释：
C is correct.
When the firm's profits exceed a pre-specified level and a value more than the par value if the firm is liquidated, participating preference shares can receive extra dividends.
ab，为什么是错的呢？
