Match list-I (Fundamental Experiment) with List-II (its conclusion) and select the correct option from the choices given below the list:

List-I                                                 List-II
A. Franck-Hertz Experiment            (i) Particle nature of light
B. Photo-electric experiment          (ii) Discrete energy levels of the atom
C. Davison-Germer Experiment       (iii) Wave nature of electron
                                                             (iv) Structure of atom

Finally, the Davisson-Germer experiment directed a beam of electrons at a nickel crystal and recorded the intensity of electrons scattered at various angles. A strong intensity peak appeared only at particular angles that satisfied Bragg’s law for diffraction, namely

$$2d\sin\theta = n\lambda,$$

where $$d$$ is the inter-planar spacing of the crystal, $$\theta$$ is the glancing angle, $$n$$ is an integer, and $$\lambda$$ is the wavelength of the incident waves. Inserting the de Broglie relation $$\lambda = \dfrac{h}{p}$$ with $$p$$ the electron momentum reproduced exactly the observed angles. Those diffraction fringes are possible only if electrons possess wave character. Hence this experiment confirmed the wave nature of the electron

$$C \;\; \longrightarrow \;\; (iii).$$