According to a recent encyclopedia entry about dog breeds, Labrador retrievers come in two specific breeds: English and American. The article cites six studies from several scientific journals about dog breeding showing that males of both breeds usually average 29-41 kg (65-90 lb) in weight, and females usually average 25-32 kg (55-70 lb) in weight. Anna’s female Labrador retriever weighs 38 kg (83 lb).

What does Anna’s dog’s weight indicate about the reliability of this source?
This is still a reliable source because it clearly cites scientific research.
This is still a reliable source because it is a printed book, not the Internet.
This is no longer a reliable source because Anna disproved the studies.
This is no longer a reliable source because Anna’s dog’s weight is in the range for males.