I agree - I didn't choose D because it felt like a stretch to assume that hand motion from sign language uses the same extent of physical exertion as speech. Two completely different parts of the body.

I fear I overthought this question and E just sounded too good to be true

Couldn't the logic behind why E isn't correct also be used to show that C isn't correct? To explain, just like how with E, if someone gets a common cold they aren't necessarily at risk for an iatrogenic disease, with C people who have a common cold and don't die, they may not (or it is very unlikely) soon die of another cause.

I was thinking the same thing