[单选题]
In the Atwood machine shown in Fnov- 4x /hvz 7btt:f3hig. 4-1, if M ed6pv.k3: uekznls*3 = 0.60 kg and m = 0.40 kg, what is the magnitude of theukpvn:el ds .*e36z3 k 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. $0.98 \; m/s^2$