I plan to go to China in February then come back to the Unites States twice, what visa should I get?

I am going to the Shanghai area at the end of February and then coming back to the Unites States in March, going back to China until June and then traveling back to the United states one more time then traveling back to China and staying for at least two months. During this time I plan to travel around the nearby countries around China. I guess I'm just not completely sure what kind of visa I should be applying for.