Read the following article and select the best answer. Article: If you've ever seen the way dog people interacted with their pets, it comes as no surprise that there's some germ-exchanging going on there. A new study indicates that dog ownership specifically may be one of the biggest single contributors to what kinds of microbes live on your skin. A team of researchers led by Se Jin Song at the University of Colorado, Boulder, took swabs of the tongues, palms, forehead and feces of members of 60 family households. Some of the families had children or household pets and some did not; dogs were the only pets swabbed. Researchers then analyzed the DNA of the bacteria they found to determine how diverse the bacteria populations were. Not surprisingly, family members who lived together had more bacteria in common than members of separate households. Bacteria on the skin were especially similar within households, probably because we pass microbes through the air, through direct contact, and via the surfaces we touch. The most surprising finding, however, was the large bacteria contribution Fidonad made. The skin bacteria of dog owners from different households was almost as similar as if they'd cohabited without a dog. Put another way, you and a friend across town who both own dogs share a skin ecosystem as alike as a married couple does. The reason for this appears to be that dogs harbor some kinds of bacteria that are rare on human skin. One in particular, a family of bacteria called Methylophilaceae, was abundant in the mouths of dogs sampled as well as the skin of their owners--indicating "a common occurrence of oral-skin transfer between dogs and their owners," according to the results published in the journal eLife. Question: From the study, we know that _ - some kinds of bacteria live on our skin because of dog ownership. - nobody finds it surprising that there should be some germ-exchanging between dogs and their owners. - only dog ownership contributes to the sort of microbes that live on our skin. - there would most probably be no microbe on our skin if it were not for dogs.
A:
some kinds of bacteria live on our skin because of dog ownership.