The Difference Between Black Market and Gray Market Activities Is

The difference between black market and gray market activities is:

A) while neither are included in GDP, black market items are illegal and gray market items are not.
B) while neither are include in GDP, gray market items are illegal and black market items are not.
C) black market items are very rare and difficult to find, and gray market items are more commonplace, like babysitting.
D) black market items are typically expensive items, and gray market items are not.