Consider the following experimental observations:
(i) Existence of a threshold frequency in photoelectric emission from a metal.
(ii) Formation of interference fringes when light passes through a double-slit arrangement.
(iii) Diffraction pattern obtained when electrons are scattered by a nickel crystal (Davisson–Germer experiment).
(iv) Linear variation of stopping potential with frequency for photoelectric emission.
Which set of TWO observations, taken together, gives direct experimental evidence for the dual nature (wave as well as particle) of light?
a) (iii) and (iv)
b) (i) and (ii)
c) (ii) and (iii)
d) (i) and (iv)