How Was De Broglie's Theory of the Waviness of Matter

Multiple Choice

How was de Broglie's theory of the waviness of matter first confirmed?

A) By passing a neutron beam through a double- slit experiment and observing the pattern of impacts on a screen.
B) By passing an electron beam through a metal foil and observing the pattern of impacts on a screen.
C) By allowing two electrons to pass through each other.
D) By passing an electron beam through a single slit and observing the pattern of impacts on a screen.
E) By careful microscopic investigation of individual electrons.