CellFrameLabelMargins is an option for cells that specifies the absolute margins in printer's points between a cell's frame and the labels around the frame.
CellLabelMargins is an option for cells that specifies the absolute margins in printer's points around a cell label.
ChartElements is an option to charting functions such as BarChart that specifies the graphics to use as the basis for bars or other chart elements.
Check
(Built-in Mathematica Symbol) Check[expr, failexpr] evaluates expr, and returns the result, unless messages were generated, in which case it evaluates and returns failexpr. Check[expr, failexpr, ...
Context
(Built-in Mathematica Symbol) Context[] gives the current context. Context[symbol] gives the context in which a symbol appears.
ContextToFileName["context"] gives the string specifying the file name that is by convention associated with a particular context.
ControllableModelQ[ss] yields True if the StateSpaceModel object ss is controllable, and False otherwise.
CounterAssignments is an option for selections that sets the value of a specified counter.
CounterIncrements is an option for selections that specifies whether the value of a specified counter is incremented by one.
Cyan
(Built-in Mathematica Symbol) Cyan represents the color cyan in graphics or style specifications.