The answer is Letter C, to whack into something
It entails being out of touch with reality, where your optimism isn't grounded in comparison to the situation you're in.
For example, imagine climbing Mount Everest and you underestimate the weather, which are underestimating obstacles and risks.
Answer:
Global life expectancy is the average age that people live to be. This is not a national life expectancy where we look only at one country and is on a global level. The industrial revolution impacted life expectancy by raising wages, living conditions. New technology was invented and many breakthroughs in sanitation were made.