[单选题]
A 500-N person stands on a uniform board of weight 100t :rxbiod8m*eda+nc(4p7mh gqrw,/2 N and length 8.0 m. c6hxv rj66 9cy The board is supported at each end. If the support force at the right end is three times that at the left end, how far from the right 6vh j 6cy6r9cxend is the person?
A. $4.0 \; m$
B. $2.0 \; m$
C. $1.6 \; m$
D. $6.4 \; m$
