John Runs a Small Bottle Shop in Inner- City Sydney

John runs a small bottle shop in inner- city Sydney. To avoid the big price discounters he has developed relationships with local residents and provides a free delivery and pickup service when they hold parties. He has also developed a relationship with local boaties who operate cruises around the harbour. Each of these groups of customers require a slightly different product range and pricing strategy. John is engaging in:

A) differentiated marketing.
B) entrepreneurship.
C) concentrated marketing.
D) undifferentiated marketing.
E) portfolio marketing.