1.C.giving为正确选项
lose no time (in) doing sth“赶紧做某事”的意思,固定用法.
2.B.seated为正确选项
seat做动词用时,主语（包括逻辑主语）是人,要用被动形式.
3.个人对楼主的原句Whom would you rather_____with you George or me?有疑问.原句应是肯定句型 would rather sb do sth 变成的疑问句,但按现代英语语法,would rather 是没有would rather sb do sth 的用法的.请楼主检查,是否把would like 误打成了 would rather?