[单选题]
What magnitude force does Jon0jzt7/b( tewiat. q/id;p q,ati4qe nr7han need to exert on the physics book to keep the rope from slitq,qpdna.;i/qe 7 4ripping?
A. $M g$
B. $\mu_{k} M g$
C. $\mu_{k} M g / \mu_{s}$
D. $\left(\mu_{s}+\mu_{k}\right) M g$
E. $M g / \mu_{s}$
