This reflects the main conclusion that society wouldn’t accept replacing paper money with a system where the government records transactions electronically. The answer summarizes this by stating that society would reject such a system. (Note that “in lieu of” means “instead of.”)

This restates a premise. The columnist argues that people "are rightly distrustful of governments with too much power" to support the conclusion that society wouldn't accept a potential new economic system. Since it supports another claim, it can't be the main conclusion.

This summarizes the context of the stimulus. It proposes a potential new economic system—one in which paper money is no longer needed—which sets the stage for the columnist to explain why society would not accept this system: it gives the government too much power.

The stimulus doesn’t make this claim. The columnist notes that people are “rightly distrustful of governments with too much power” but doesn’t conclude that people would be right to distrust this new economic system. The columnist simply concludes that people wouldn’t accept it.

This misstates the conclusion. The columnist concludes that society wouldn't willingly accept a system where the government records all transactions, not that it would be impossible for a government to use it. A government could perhaps impose such a system despite resistance.