In the three$-$phase transformer shown in the attached figure:

a$)$ Determine the clock number.

b$)$ Identify the connection type according to standardized nomenclature.

c$)$ Calculate the ratio between the three$-$phase voltage transformation ratio mTm$\_$TmT$$ and the phase voltage transformation ratio mmm$,$ assuming that the primary is the high$-$voltage $($H$.$V$.)$ side.