The close agreement between Mendeleev's predicted properties for eka-aluminium and the actual properties of gallium best demonstrates which merit of his table?

1. Mendeleev left a gap and predicted gallium's atomic mass, density, and oxide formula. 2. When gallium was discovered, its measured values matched closely (e.g. density 5.9 vs 5.94). 3. This proved his table could foretell undiscovered elements, a key merit. 4. Rule out A and D: those were demerits Mendeleev's table could not handle. 5. Rule out B: isotopes were not even known in Mendeleev's time. _Source: Balbharati (Maharashtra Board) Class 10 Science & Technology, Ch 2 "Periodic Classification of Elements", p.28_