Celebrate National Dog Day With This Quiz on Man's Best Friend

What is the most popular breed of dog in the U.S.?

On the ABC News app? Click HERE to watch this interactive video.

It's National Dog Day today, and to celebrate, ABC News went to a dog park in Los Angeles to quiz people about dogs.

Take the interactive quiz above to see how much you know about man's best friend.

Questions in the quiz include:

-Which of the following dogs has a star on the Hollywood Walk of Fame?
-What is the most popular breed of dog in the U.S., according to the American Kennel Club?
-What is the speediest dog, running as fast as 45 mph?
-What dog often has six toes?
-The most expensive dog to have reportedly been bought was a Tibetan Mastiff for around $1.5 million in what country?