According to your text, in the broadest terms, the "marketplace" refers to

A) wholesale and retail environments.
B) brick-and-mortar stores and the Internet.
C) the four Ps.
D) channels that are accessible to a given customer.
E) the world of trade.

Marketplace

A venue, either physical or digital, where buyers and sellers come together to exchange goods and services.

Wholesale and Retail Environments

The physical and market settings in which wholesale and retail transactions take place, each having its specific characteristics and requirements.

Brick-and-mortar Stores

Physical retail outlets located in buildings as opposed to online or digital shops.