Choose B, because military national education was transmitted from abroad in the late Qing Dynasty. Cai Yuanpei thinks that he is not an education in an ideal society. However, in China, it is "a person who has to adopt today". The main reasons are:

(1) From the external environment, China is in a state of "desperate self-defense, and the state power lost for many years cannot be restored unless it relies on force."

(2) As far as the domestic situation is concerned, in order to break the situation that soldiers become a "national special class", it is necessary to "make the whole country a soldier, otherwise its power cannot be averaged". It can be seen that Cai Yuanpei advocated military national education in order to defend himself externally and oppose the military's power rule internally. It can be seen that the implementation of military national education is to resist foreign aggression and oppose the autocratic rule of domestic soldiers. So what? One-sided BC is wrong. I hope you are satisfied.