The author writes that whoever develops a plan to make children useful should "have his statue set up for a preserver of the nation." this means that the person who solves this problem deserves

Trade will take place: a. if the maximum that a consumer is willing and able to pay is less than the minimum price the producer is willing and able to accept for a good. b. if the maximum that a consumer is willing and able to pay is greater than the minimum price the producer is willing and able to accept for a good. c. only if the maximum that a consumer is willing and able to pay is equal to the minimum price the producer is willing and able to accept for a good. d. none of the above.