A Spring Scale Is Fastened to the Ceiling of a Railway

Multiple Choice

A spring scale is fastened to the ceiling of a railway car. When a 1.0-kg block is hung from the scale, it reads 12 N and is oriented as shown in the figure. What is the approximate acceleration of the car as measured by an observer at rest on the ground outside of the car?

A) 7 m/s² to the right
B) 7 m/s² to the left
C) 12 m/s² to the right
D) 12 m/s² to the left
E) It is impossible to calculate since the angle $\theta$ has not been given.