Efficiency in a market is achieved when A. a social planner intervenes and sets the quantity of output after evaluating buyers' willingness to pay and sellers' costs. B. all firms are producing the good at the same low cost per unit. C. no buyer is willing to pay more than the equilibrium price for any unit of the good. D. the sum of producer surplus and consumer surplus is maximized.

Employees at a library check out books to patrons. books have an isbn and a name. the library sometimes has multiple copies of the same book. books have one or more authors. a patron is an individual who has an active (non-expired) library card. for each library card, we store the person's first and last names and their address. for each employee, we store their employee id, current salary, first and last name and their address. we also store the employee id of their current manager. each time we check out a book to a patron we need to store the date of the transaction, the employee who checked out the book to the patron, and the library card of the patron. some employees have library cards. if an employee patron turns in a book late, the fine that they pay is a percentage of their salary. some employees are authors who have library cards—they are allowed to check out as many books as they like.

Blue spruce corp. has the following transactions during august of the current year. aug. 1 issues shares of common stock to investors in exchange for $10,170. 4 pays insurance in advance for 3 months, $1,720. 16 receives $710 from clients for services rendered. 27 pays the secretary $740 salary. indicate the basic analysis and the debit-credit analysis.

In the context in which your reading material uses the term traffic patterns are