$A$ catalyst increases the rate of reaction because it

$A$ catalyst poison makes the catalyst ineffective because...

In a homogeneous catalysis:

For the conversion of ozone to oxygen in the atmosphere,nitric oxide in the gaseous phase acts as:

Which of the following statements is most accurate regarding a catalyst?

Iron $(III)$ catalyses the reaction between iodide and persulphate ions,in which
$A$. $Fe^{3+}$ oxidises the iodide ion
$B$. $Fe^{3+}$ oxidises the persulphate ion
$C$. $Fe^{2+}$ reduces the iodide ion
$D$. $Fe^{2+}$ reduces the persulphate ion
Choose the most appropriate answer from the options given below: