Answer: option C: 12.0 N
The women pulls the dog with a force of 20 N at an angle of
from the horizontal. we can write this in terms of components.
Horizontal component=

Vertical component =

The horizontal component would tend to make the dog move forward.
On the other hand, the vertical component would tend lift it off the ground.
Hence, the correct option is C: 12.0 N.