The verification of what key prediction convinced scientists that Einstein's General Theory of Relativity was correct? Select one alternative:
O A. The dependence of clocks on the strength of the local gravitational field.
O B. The discovery of the expansion of the Universe.
O C. The discovery of black holes.
O D. The apparent movement of stars close to the sun in the sky during a total solar eclipse.
O E. Explaining the perihelion precession of Mercury.