Respuesta :
Article X of the Covenant of the League of Nations required defense of member nations. The correct option among all the options that are given in the question is the second option or option "B". This was a military agreement. I hope that the answer has come to your help.
The answer is letter B. defense of member nations.
When a nation is experiencing an external aggression,
the countries that have signed the treaty will have to lend a hand in order to
keep the nation safe.