Marco is conducting an experiment on training certain breeds of dogs. He wants to know how long, on average, it would take to teach a Labrador to fetch an object. He gets a group of dogs to conduct his experiment. 5 of the dogs are Labradors and 3 of the dogs are Dalmatians. What is the population and sample in this experiment?

A) The population is all Labradors, and the sample is the 5 Labradors that Marco trained.
B) The sample is all Labradors, and the population is the 5 Labradors that Marco trained.
C) The population is all Labradors, and the sample is the 8 dogs that Marco trained.
D) The sample is all Labradors, and the population is the 8 dogs that Marco trained.