Explanation:
its either a or d however i say the best choice is d
-- Bathroom tiles are usually cool, so water condenses on them
when you take a hot bath or shower in the room.
-- The natural result is that a smooth tile would become slippery,
exactly when you're walking around with wet feet and nothing on them ...
a dangerous situation.
-- In order to circumvent this safety hazard, the tiles in the bathroom
should be rough, especially on the floor.