 What are the four hypotheses Charles has about how he might have survived the plague?
There should be an epitaph for every man, big or little, but a really grand and special one for Loner Charlie. New York lay quietly below him. The largest cotton crop ever was forecast and rumors from Mexico had it that no one had died from scorpion bite in several weeks. A month later the meat animals, the birds and the household pets began dropping as rapidly as the flies which had dropped earlier. The panic which had begun with the death of the animals was quieted somewhat by the fact that humans seemed immune to the pandemic. And now.... "I've got to find out," Charles told himself. Before the plague the Bureau of Vital Statistics had been one of man's crowning achievements.
 He’s too normal to get it; pure chance; he’s a saint; immunity
 He’s too strange; he’s a prophet; the odds were against him; he got a vaccine  He’s a nice guy; pure chance; he’s a prophet; he received medical treatment.  He’s healthier than everybody; pure chance; he knows a good doctor; he wore a mask  He’s too normal to get it; pure chance; he’s a saint; immunity