Question $2(30$ pts$.)$: Look at the question's picture please. Consider $5$ points in two$-$dimensions space shown in the table:

Suppose two clustering methods Clustering A and Clustering B$,$ are applied only on these points. The clustering results are given in the following table:

These points are distributed in the classes as the following:

a$)$ Find ${}_1$ of Clustering $A$

b$)$ Which of the two previous clustering methods: Clustering $A$ or Clustering $B$ is better when using purity measure?