[单选题]
A 400-N box is pushed mh4 ; ,bs:hjquyskc6:uqni)z.; 7 p/*mqdsysg uode86p an inclined plane. The plane is 4.0 m long and rises 2.0 endsoqisy g/pz* m u.d q8)6;7m. If the plane is frictionless, how much work was done by the push?
A. $1600 \; J$
B. $800 \; J$
C. $400 \; J$
D. $100 \; J$
