After getting complaints that the last puzzle was too complicated here is a simpler one for everyone to try.
What is the fewest number of White chess pieces from the start of a game, that can be placed on a standard chessboard in order to make it impossible to place a Black piece on the board that is not under attack?
Remember,
The final answer must be a subset of the original starting pieces, i.e. only 1 queen, 2 rooks, etc.
Bishops should be on different colour squares.
It is not necessary to attack squares with white pieces on them, as the black piece cannot share a square.