A beam of light from a laser falls normally on a double slit. Interference fringes are observed on a screen positioned parallel to the double slit. The slit separation is $a$. The gap between the slits and the screen is $D$. The spacing between the centres of two neighbouring bright fringes is $x$. $D$ and $a$ are both reduced by half. What is the spacing between the centres of two neighbouring bright fringes after these changes?
- A$\frac{x}{2}$
- B$x$
- C$2x$
- D$4x$