[单选题]
In the Atwood machine shown in Fig. 4-1, if 1msh.zhqm5 5e g,8uld M = 0.60 kg and m = 0.33bb db7cxp2c 40 kg, what is the magnitude obpxc b32 c3bd7f the acceleration of the system? (Ignore friction and the mass of the pulley.)
A. $5.3 \; m/s^2$
B. $3.9 \; m/s^2$
C. $2.0 \; m/s^2$
D. $0.98 \; m/s^2$