我美國公民，給父母申請綠卡，父母在國內。我有幾個問題不知道怎麽填：
問題1
Security and Background: Medical and Health Information的部分有個疫苗的問題
Do you have documentation to establish that you have received vaccinations in accordance with U.S. law? 
Yes or No.
如果選了no, 就會跳出來一個框要解釋。
我是應該選yes 還是no呢？我父母七十多了，在國內應該就是小時候被要求打什麽就打過什麽，不清楚他們有沒有記錄，這個情況怎麽回答這個問題啊？
問題2
Are you a member of or affiliated with the Communist or other totalitarian party?
我爸是共產黨員，那是不是就得回答yes. 然後就被要求解釋，那如果yes的話，要解釋啥呀？填yes的話會影響immigration visa 申請嘛？
問題3
表的最後有個問題Do you want the Social Security Administration to issue a Social Security number and a card?
這個是填yes吧？
謝謝！
