The masses of 10 kg and 20 kg, respectively, are connected by a light spring as shown in the figure. A force of 200 N acts upon the 20 kg mass. At the instant shown, the 10 kg mass the acceleration of `12m//s^(2)`. The acceleration of 20 kg mass is
A. `12m//s^(2)`
B. `4m//s^(2)`
C. `10m//s^(2)`
D. Zero
