A single-wavelength light beam is incident normally on a double slit. A pattern of interference fringes is seen on a screen. The separation between the double slit and the screen is $0.60\,\text{m}$, and the fringe spacing is $1.8\,\text{mm}$. If the distance between the double slit and the screen is increased by $0.90\,\text{m}$, what will the new fringe spacing be?
- A$1.2\,\text{mm}$
- B$2.7\,\text{mm}$
- C$4.5\,\text{mm}$
- D$5.4\,\text{mm}$