The text provides three primary strategic approaches $($differentiation$,$ cost$,$ and response$)$ for achieving competitive advantage. Provide an example of each. Support your choices.

Choose the correct example of differentiation and its explanation below.

A$.$ Hewlett$-$Packard, as it demonstrates flexibility in both design and volume changes in the volatile world of PC$.$

B$.$ Hunter Fan, as it guarantees delivery in $3$ days.

C$.$ Hunter Fan, as it's a premier maker of quality ceiling fans that lower heating and cooling costs for its customers.

D$.$ Hewlett$-$Packard, as it provides personal computers at the best and cheapest prices.