The diagram represents a wooden beam with weight $20\,\text{N}$. Its centre of mass is marked $M$. A pivot is positioned at one end of the beam. An upward force, $F$, holds the beam in a horizontal position. What is the magnitude of $F$?
- A$12\,\text{N}$
- B$20\,\text{N}$
- C$30\,\text{N}$
- D$33\,\text{N}$