When Lyme Disease Was First Being Investigated, the Observation That Frequently

When Lyme disease was first being investigated, the observation that frequently only one person in a household was infected was a clue leading to the discovery that the disease was transmitted by arthropod bites. Why was this so?

A) If the infection is spread by the bite of an arthropod, it wouldn't spread easily by respiratory secretions, direct contact, or sexual contact between individuals within the family.
B) Mosquitoes (an example of arthropods) are never inside a house. They are strictly outdoor insects, so they couldn't spread the infection inside the household.
C) Mosquitoes (an example of arthropods) only bite once in their lifetime. As such, they can only transmit the illness once before they die. Even if an infected mosquito was inside a house, it could only infect one human.
D) Arthropods lose their mechanical ability to bite a human after a single bite, much like certain bees lose their stinger after a single sting. This prevents them from transmitting the infection to more than one individual in a household.
E) These are all valid reasons that support the theory that Lyme disease must be transmitted by arthropod bites.