The correct answer is C) five times the full load current. In an induction-type motor with a squirrel-cage rotor, a significantly higher starting current is required to overcome the high initial resistance and produce the necessary starting torque. At standstill, the motor's rotor is stationary, resulting in a low reactance and a high resistive component. This combination requires a much higher current, typically 5 times the full load current, to generate the required starting torque. The other options are incorrect because: A) half the full load current would be insufficient to produce the necessary starting torque; B) equal to the full load current would also be insufficient; and D) ten to twenty times the full load current, while possible, is generally not required for successful starting in a 15 HP induction-type motor.