This is a musical term used to describe the tempo of the music speeding up
He is calling attention to the issue. President Wilson would not call the session if the topic is of policy changes and talk about going to war. He also isn't apologizing, otherwise he would use the word, "I'm sorry for calling this session." I also don't think you use "diverse" one big word in a sentence, diverse should be multiple words that aren't general. Therefore, calling attention to the issue is the most logical.
Answer:
one half rest because each has a beat value of 2 that would add up to 4