A$.$ Wal$-$Mart, as it provides the fast product delivery to the customers.

B$.$ Hard Rock Cafe, as it engages the customer with classic rock music.

C$.$ Wal$-$Mart, as it has the low overhead and huge buying power to pressure its suppliers into concessions.

D$.$ Hard Rock Cafe, as it provides the aroma of fresh coffee or freshly baked bread.