[单选题]
An object of mass m is hanging by a string from the ceilinz9)np y de c:w3c7x(z g9t*pnsg of an eq yt,hdonl j5 )/n.cwh6g7b a(f 09fwdlevator. The elevator is moving upward, but slowing down. What is the tension in the stringwt6w,df5dyo)j gnl70a 9n .hbqfh(/ c?
A. less than mg
B. exactly mg
C. greater than mg
D. zero
