Pandas merge_asof Quiz: Direction, Tolerance and Exact Matches

Pandas merge_asof Quiz: Direction, Tolerance and Exact Matches

Choose one answer. Each attempt draws 10 of 20 questions; the practice pass mark is 8/10. Original topic practice, not an official exam. Match sorted observations by nearby keys without assuming equality joins.
1 of 10
Left key is 2; right keys are 5 and 9. With backward, what happens?