Answer:
In regretting the past
Explanation:
When you combine "retro" and "spec" you get the definition "to look back." So, this basically means when you are thinking back to the past. The narrator is most definitely regretting the past(feeling bad about what they did before) because they say that they should have taken better notes.
Anticipating the past is impossible because anticipating means looking forward to. You can't look forward to something that already happened.
Considering the past means to just think about the past. The narrator wasn't just thinking about the past, they were feeling bad about it. They were regretting it, not considering it.
