The answer is "a. True".
Positive reinforcement works by showing an inspiring/strengthening upgrade to the individual after the coveted conduct is displayed, making the conduct bound to occur later on.
Negative reinforcement happens when a specific boost (for the most part an aversive upgrade) is expelled after a specific conduct is shown. The probability of the specific conduct happening again later on is expanded in view of evacuating/maintaining a strategic distance from the negative result.