フリー問題

問題文

An advertising team studies why some steps never appear as a separate stage. The steps in question are the selection of columns and the filtering of rows. What do these steps have in common?

選択肢

1. Those steps stay narrow because the rows of one output partition all come from the same input bucket.
2. Those steps stay narrow because the rows of one output partition all come from the same input grouping.
3. Those steps stay narrow because the rows of one output partition all come from the same input partition.
4. Those steps stay narrow because the rows of one output partition all come from the same input file.