Final answer:
Producer surplus increases by $100 for John, and potentially up to $200 in total if considering Jasmine's surplus as well, assuming she would have accepted $300. The most accurate answer is that producer surplus increases between $100 and $200.
Step-by-step explanation:
When the university increases the payment for tutors from $300 to $400 per semester, producer surplus increases due to this price change. Producer surplus is defined as the difference between what producers are willing to accept for a good or service versus what they actually receive. Since John was willing to tutor for $300, his producer surplus increases by $100 when he receives $400. Jasmine entering the market does not affect the calculation of the increase in John's producer surplus. Therefore, producer surplus rises by $100 for John.
Now, considering Jasmine's entry into the market, since Jasmine was not previously in the market at the lower price, we can only speculate that for her, the producer surplus would be less than or equal to $100, depending on her willingness to accept the lower price which we do not have data on.
Considering both John and Jasmine, the total increase in producer surplus would be at least $100 (for John alone), and potentially up to $200 if we assume Jasmine would also have been willing to tutor for $300 initially (getting the full $100 surplus as well). Answer choice (b) between $100 and $200 is the most accurate, as producer surplus rises by $100 from John, and potentially up to $100 from Jasmine.