The diagram illustrates the labour demand and supply curves for a firm. The starting wage rate is shown as $W_0$, and the equilibrium quantity of labour employed is $L_0$. A trade union representing all workers secures a higher wage rate of $W_1$. What is the size of the unemployment created by this rise in wages?
- A$OL_1$
- B$L_0L_2$
- C$L_1L_0$
- D$L_1L_2$