Cynthia has a fractured finger. if she goes to the doctor, she'll get some medicine that will decrease the pain. she decides it's worth her time go to the doctor. what type of reinforcement is this?

This is a negative reinforcement.

Explanation:

Negative reinforcement is a term described by BF Skinner in his theory of operant conditioning. In negative reinforcement, a response or behavior is reinforced by stopping, removing or avoiding a negative outcome or aversive stimulus.  Aversive stimuli tend to involve some kind of discomfort, be it physical or psychological. Behaviors are reinforced negatively when they allow you to escape from aversive stimuli that are already present or allow you to completely avoid the aversive stimuli before they happen.

In this case, Cynthia will go to the doctor, to take a remedy (behavior) that will lessen the pain of his fractured finger (removal of the aversive stimulus).

This is not a positive reinforcement, because positive reinforcement can be defined as reinforcing positive behavior through praise. and that's not what's happening with Cynthia.

when the united states took over

the answer is d.index