In Young's double slit experiment,the fringe width is $1 \times 10^{-4} \ m$. If the distance between the slit and screen is doubled,the distance between the two slits is reduced to half,and the wavelength is changed from $6.4 \times 10^{-7} \ m$ to $4.0 \times 10^{-7} \ m$,what will be the value of the new fringe width?

• A
  $0.15 \times 10^{-4} \ m$
• B
  $2.0 \times 10^{-4} \ m$
• C
  $1.25 \times 10^{-4} \ m$
• D
  $2.5 \times 10^{-4} \ m$