Part A What is the purpose of the dot convention? What is the purpose of the dot convention? to determine where mutual inductance is strongest to establish the reference polarity for induced voltages to determine where induced voltages are equal to establish the reference direction for induced currents

Option B, to establish the reference polarity for induced voltages

Explanation:

Dot basically indicates the polarity of the electrical windings. Currents entering and leaving the same dotted ends will produce magnetic flux in same direction while the current entering at one dotted end and leaving at another dotted end will produce opposing magnetic flux.

Thus it is clear that dot represents the terminals having same phases of induced AC voltages so that only one winding is loaded at a time.

Hence, option B is correct