All Labrador retrievers love playing fetch. Only German shepherds love protecting their home. Some dogs are easy to train. Brittany' s dog loves playing fetch and loves protecting her home. Which one of the following statements must be true? ["Brittany 's dog is easy to train.", "Brittany's dog is half Labrador retriever and half German shepherd, and her dog is also easy to train.", "Brittany 's dog is a Labrador retriever.", "Brittany 's dog is a German shepherd."]