Wow, this is a tricky one.

A - definitely not

B also sounds good, but since you don't know WHICH cases that could mean leaving 10-20 subtabs open at once, and they wouldn't all necessarily be from today.

I think C is wrong. I think they phrase here is "dozens of cases". Since History can only show 10 max, I think the correct answer is actually D - Define a custom list view. You can easily create a List View with Last Modified Date=TODAY and then just quickly to jump to a list of EVERY Case modified today (assuming you edited it, not just viewed it) with just 1 or 2 clicks, depending on if you set it as the default list View (pinned) also.

so I think the best answer here is actually D. But it's a horrible question and very subjective to how you work.