How many glucose molecules are required for the formation of $52$ pyruvic acid molecules at the end of glycolysis?

How many $NADH + H^+$ molecules are produced during the process of glycolysis?

Number of $ATP$ molecules formed in glycolysis by substrate-level phosphorylation is . . . . . . .

The formation of $Acetyl-CoA$ from pyruvic acid is the result of its

Given below are two statements: One is labelled as Assertion $A$ and the other is labelled as Reason $R$:
Assertion $A:$ $ATP$ is used at two steps in glycolysis.
Reason $R:$ First $ATP$ is used in converting glucose into glucose-$6$-phosphate and second $ATP$ is used in conversion of fructose-$6$-phosphate into fructose-$1,6$-bisphosphate.
In the light of the above statements,choose the correct answer from the options given below:

Which enzyme is active only in the presence of $Mg^{2+}$, $Mn^{2+}$, or $Zn^{2+}$?