Word processing software includes spell checkers and grammar checkers, but there are some errors that will never be caught by these tools. Which of the following errors would be caught by a computer software spell checker?

Whether "irregardless" or "regardless" is correct.

Whether "your" or "you're" is correct.

Whether $$10\mathrm{.}00$ or $$100\mathrm{.}00$ is correct.

Whether "now" or "not" is correct.