BubbleSizes is an option to BubbleChart and related functions that specifies the range of sizes used for bubbles.
ButtonBoxOptions -> {opt_1 -> val_1, opt_2 -> val_2, ...} is an option for cells that specifies settings for buttons within the cell.
ButtonNotebook[] gives the notebook, if any, that contains the button which initiated the current evaluation.
ButtonSource is an option for the low-level function ButtonBox that specifies the first argument to give to the ButtonFunction for the button when the button is active and is ...
CancelButton[] represents a Cancel button in a dialog that closes the dialog window when clicked.CancelButton[action] represents a button labeled Cancel that evaluates action ...
CellGroupData[{cell_1, cell_2, ...}] is a low-level construct that represents an open group of cells in a notebook. CellGroupData[{cell_1, cell_2, ...}, 1] represents a cell ...
CellLabelAutoDelete is an option for Cell which specifies whether a label for the cell should be automatically deleted if the contents of the cell are modified or the ...
Center
(Built-in Mathematica Symbol) Center is a symbol that represents the center for purposes of alignment and positioning.
CharacterEncoding is an option for input and output functions which specifies what raw character encoding should be used.
ChartLayout is an option to charting functions which specifies the overall layout to use.