Pyruvate dehydrogenase activity during aerobic respiration requires

The mineral activator required for the carboxylase enzymes of the $TCA$ cycle is

Assertion: In Krebs cycle,there is a one step where substrate level phosphorylation occurs.
Reason: During the formation of succinyl $\text{CoA}$ to succinic acid,a molecule of $\text{GTP}$ is synthesized.

Which enzyme is necessary for the following process?
Pyruvic acid $+ CoA + NAD^+ \rightarrow$ Acetyl $CoA + CO_2 + NADH + H^+$

The pyruvic acid formed in Glycolysis is oxidized to $CO_2$ and $H_2O$ in a cycle called

Which process requires enzymes present in the mitochondrial matrix?