Which of the following represents the correct order of increasing first ionization enthalpy for $\text{Ca}$, $\text{Ba}$, $\text{S}$, $\text{Se}$ and $\text{Ar}$?

1. Noble gases have the highest ionization enthalpy ($\text{Ar}$ is highest).2. Across a period, I.E. increases; down a group, I.E. decreases.3. $\text{Ba}$ and $\text{Ca}$ are in Group 2. $\text{Ba}$ is below $\text{Ca}$, so $\text{Ba}<\text{Ca}$.4. $\text{S}$ and $\text{Se}$ are in Group 16. $\text{Se}$ is below $\text{S}$, so $\text{Se}<\text{S}$.5. Non-metals ($\text{S},\text{Se}$) have higher I.E. than metals ($\text{Ca},\text{Ba}$).Combined order: $\text{Ba}<\text{Ca}<\text{Se}<\text{S}<\text{Ar}$.