Forces and equilibrium — practice question

A particle $P$ weighs $10\,\text{N}$ and is in limiting equilibrium on a rough horizontal table. The forces drawn in the diagram are the weight of $P$, an applied force of magnitude $4\,\text{N}$ acting on $P$ at $30^{\circ}$ above the horizontal, and the contact force from the table on $P$ (the resultant of the frictional and normal components) with magnitude $C\,\text{N}$.