Ray OP strikes plane mirror MN at an angle of incidence of $40^{\circ}$. The mirror is then turned by $10^{\circ}$, as shown by the dashed line. The direction of the incident ray OP stays the same. What is the new angle of incidence?
- A$30^{\circ}$
- B$40^{\circ}$
- C$50^{\circ}$
- D$60^{\circ}$