In a YDSE light of wavelength\[\lambda =5000\]\[\overset{\text{o}}{\mathop{\text{A}}}\,\]is used which emerges in phase from two slits a distance \[d=3\times {{10}^{-7}}m\] apart. A transparent sheet of thickness\[t=1.5\times {{10}^{-7}}m\], is refractive index n = 1.17, is placed over one of the slits. Where does the central maxima of the interference now appear?

• A. \[\frac{D(\mu -1)t}{2d}\]
• B. \[\frac{2D(\mu -1)t}{d}\]
• C. \[\frac{D(\mu +1)t}{d}\]
• D. \[\frac{D(\mu -1)t}{d}\]