Which of the following is an example that enables a store to communicate directly with consumers inside of a store, often based on the consumer$$s exact location $($e$.$g$.$ in the middle of Aisle $7,$ browsing through the $$batteries$$ section$)?$

a$.$

In$-$window chat application

b$.$

iBeacon

c$.$

Real$-$time personal assistant

d$.$

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