(A) Wireless Modems is the answer. This is the best choice! See if you think about it, you will also come to the conclusion that the answer is (a).
1 answer is longevity 2 answer is cardiovascular system
I think the answer to this question is that it paved way to the popularity of mystery fiction. Also, a significant result of Doyle's detective mysteries is their focus on crime investigation and paying attention to details that would help in crime-fighting - which encouraged awareness during his time about it.