Safehouse Study is an option for Safehouse Room B. You can buy the receipt from Bits and Pieces in Solitude.
Study Room B
If you buy the "Safehouse Study Receipt (B)" (7600 Gold), it will be automatically added to the Household Planner in the Master Bedroom. Here you can set up the room to contain 8 empty book shelves for storage and display, two research desks with chair, a sitting area with chairs, tables, sofa and built in fountain and built in wall book cabinets.