问题如下：
If a company’s objective is to support its stock price in the event of a market downturn, it would be advised to authorize:
选项：
A.an open market share repurchase plan to be executed over the next five years.
B.a tender offer share repurchase at a fixed price effective in 30 days.
C.a Dutch auction tender offer effective in 30 days.
解释：
A is correct.
Of the three methods, only an authorized open market share repurchase plan allows the company the flexibility to time share repurchases to coincide with share price declines.
看了有问必答的解析，了解到C错误的点在于这个荷兰式拍卖是30天后才effective
那如果这个荷兰式tender offer立刻生效，有效期30天，是否符合题意的目的呢？
另外，根据tender offer的定义：公开市场要约，那么是不是也是open market操作的其中一种方式，只是价格是区间，而不是fixed？
