[单选题]
A box with a mass of M reaej v wtx:*:sms96 -vdstsc-j1 i7k6 1 u0 elbjguwk.:pvxl:q6 to on a balance in an elevator that is moving downwards. The elevjxuvj: . i0qt:l1b7kk uoc -le16w p6gator slows with an acceleration of $\frac{g}{4}$.
Which of the following gives the reading of the balance?
A. $\frac{5Mg}{4}$
B. $Mg$
C. $\frac{3Mg}{4}$
D. $\frac{Mg}{2}$
