Which element replaced eka aluminium according to the Mendeleev’s periodic table?

Gallium

The correct answer is option 3. Gallium.

The element that replaced "eka aluminium" according to Mendeleev's periodic table is Gallium.

"Eka-aluminium" was the placeholder name given by Dmitri Mendeleev for the element with atomic number 31 in his periodic table. Gallium (Ga) was discovered by Paul-Émile Lecoq de Boisbaudran in 1875, and it was found to fit the properties predicted by Mendeleev for eka-aluminium. Therefore, gallium is the correct answer.