Those in favor of using the atomic bomb argued that a mainland invasion of Japan would fail to demonstrate the power of the US Navy.
lead to massive death and destruction in civilian areas.
open the United States to criticism from Allied partners.
cost hundreds of thousands of American soldiers’ lives.

Lead to massive death and destruction in civilian areas.

Explanation:

The supporters argue the idea of releasing atomic bombs would lead to the death of many people with the destruction of cities. The atom bomb came to be known for its destruction in a wider range and damaging buildings, the terrain, and the atmosphere. By destroying civilian areas Japan would surrender in the Second World War. Japan during WW II was unbeatable because of its strong Imperial Navy controlling the Pacific Ocean and Asia.  

b

Explanation:

i would go with the last one

there are many ways of getting involved on your local party. attached you will find the brochure that describes some ideas: go ahead and visit your local hq, become a volunteer on your comnunity or struggle up for your own ideas so you can make them real.