The correct answer is A) the line current is equal to the phase current. In a three-phase, wye-wye connected transformer, the line current and phase current are equal because the phases are connected in parallel. The current divides equally among the three phases, so the line current is the same as the phase current. The other answer choices are incorrect because: B) the line current is not three times the phase current in a wye-wye connection. C) the line current is not equal to the difference of any two phase currents. D) the line current is not equal to the sum of any two phase currents.