​The problem of "double marginalization" is

A) ​The retail price being too high due to an inclusion of both manufacturer and retailer markup
B) The retail price being too low due to an exclusion of both manufacturer and retailer markup
C) The retail price being too high due to an exclusion of manufacturer markup
D) ​The retail price being too low due to an exclusion of retailer markup  

Marianne and Laura are both homemakers with children.When Laura starts to work as an unpaid volunteer at a hospital,she hires Marianne to care for her young child.In this context,the gross domestic product (GDP) will _____.

A) increase
B) decrease
C) remain unaffected
D) increase if Marianne cares for the child better than Laura
E) increase if Laura treats patients with more sincerity than the other volunteers