_________ socks 20 dollars?        [ ]

A. Is the      

B. Are they

C. Are the   

D. Is that

挖掘机行驶时，铲斗应位于机械的正前方并离地面1m左右，回转机构应制动，上下坡的坡度不得超过（）°。

A.20

B.30

C.40

D.50