Among the following,the most basic oxide is

Aluminium is diagonally related to (in periodic table)

Statement $I :$ Acid strength increases in the order given as $HF < HCl < HBr < HI$.
Statement $II :$ As the size of the elements $F, Cl, Br, I$ increases down the group,the bond strength of $HF, HCl, HBr$ and $HI$ decreases and so the acid strength increases.
In the light of the above statements,choose the correct answer from the options given below.

Which of the following is a normal element?

Which of the following is the most electropositive element?

The order of reactivity of $K$,$Mg$,$Zn$,and $Au$ with water is