Three Objects Are Moving Along a Straight Line as Shown $- 14.0 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$

Three objects are moving along a straight line as shown in the figure. Taking the positive direction to be to the right, what is the total momentum of this system?

A) $- 14.0 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$
B) $+ 14.0 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$
C) $+ 106 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$
D) $0.00 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$
E) $- 106 \mathrm {~kg} \cdot \mathrm { m } / \mathrm { s }$