Answer to Question 1
A
Answer to Question 2
Subliminal advertising is the idea that an ad can be shown for a brief moment that it is so short that it doesn't meet the threshold of consciousness, and is therefore subliminal. This somehow is captured subconsciously, and the hope is the message would compel one to buy the product advertised.
Marketers have ruled that subliminal advertising doesn't work. But, they do a lot of research in the areas of perceptual fluency. Marketers know that if you are exposed to the same billboard every day, you will start to become familiar with it, and with familiarity comes a comfortable, positive feeling, increasing the chances you will make a purchase.