Arrayformula to lookup last entry

I have this example here: https://docs.google.com/spreadsheets/d/1xK86N1P2UMcY7WwHcwVV24ECk7caMbAxXvnDeKwBLYA/edit?usp=sharing I need to have the data in column D filled in with arrayformula. The value should be the value in column B.

I've tried using combination of ROW&INDIRECT&FILTER&QUERY|VLOOKUP , but it didn't work, as if ROW() cannot be used in arrayformula. Maybe you guys have some idea that could work.