Our English teacher Miss Wang is very ________ to us. We are ________.
A：friend; friend
B：friendly; friend
C：friend; friendly
D：friendly; friends
如果一组数据a1，a2，…，an的平均数是2，那么一组新数据3a1+2，3a2+2，…，3an+2的平均数是（ ）
