Answer: (A) about 75°.
Explanation:
Ideally a transformer draws the magnetizing current, lags primary applied voltage by 90°. But the transformer also has core loss current component which will be in phase with applied voltage. And no load current is nothing but the vector summation of these two currents. Hence, the no load current will not lag behind applied voltage by exactly 90° but it lags somewhat less than 90°. It is in practice generally about 75°.