Which block element from the following are known as transition elements?

On what ground can you say that scandium $(Z=21)$ is a transition element but zinc $(Z=30)$ is not?

Which of the following elements are included in the fourth transition series?

Given below are two statements:
Statement $I$: Ferromagnetism is considered as an extreme form of paramagnetism.
Statement $II$: The number of unpaired electrons in a $Cr^{2+}$ ion $(Z=24)$ is the same as that of a $Nd^{3+}$ ion $(Z=60)$.
In the light of the above statements,choose the correct answer from the options given below:

What is the atomic number of an element having $ns^1$ electronic configuration and belonging to the $3d$ transition series?

Ionisation potential values of $d-$block elements as compared to ionization potential values of $f-$block elements are