Forces — practice question

The diagram represents a beam in equilibrium on a pivot. Two forces, $X$ and $Y$, are acting on the beam. Which calculation gives the moment of the force $Y$ about the pivot?

• A$Y \times (a + b)$
• B$\dfrac{Y}{(a + b)}$
• C$Y \times b$
• D$\dfrac{Y}{b}$