A monochromatic plane wave, moving with speed $c$ and wavelength $\lambda$, is diffracted by a small aperture. The diagram shows successive wavefronts. How long will it take for some part of wavefront GH to reach point P?
- A$\frac{3\lambda}{2c}$
- B$\frac{2\lambda}{c}$
- C$\frac{3\lambda}{c}$
- D$\frac{4\lambda}{c}$