For an analyst evaluating the common stock of a financial institution that reported a small loss for the year just ended, the price multiple that is least likely to be meaningful is:()

A. price to cash flow.

B. leading price to earnings.

C. trailing price to earnings.

探究燃烧条件的实验装置如图所示。

（1）由该实验得，可燃物燃烧的条件是：

① _____________；②_____________。

（2）实验中发生反应的化学方程式为________________。