A 3-phase, 440 V, 50 Hz, 4-pole slip ring induction motor is feed from the rotor side through an auto-transformer and the stator is connected to a variable resistance as shown in the figure. 3-phase 50 Hz, supply: Auto Transformer Induction Motor Q mmm +220 V R The motor is coupled to a 220 V, separately excited d.c generator feeding power to fixed resistance of 10 2. Two-wattmeter method is used to measure the input power to induction motor. The variable resistance is adjusted such the motor runs at 1410 rpm and the following readings were recorded W 1800 W, W = == - 200 W. = The speed of rotation of stator magnetic field with respect to rotor structure will be (A) 90 rpm in the direction of rotation (B) 90 rpm in the opposite direction of rotation (C) 1500 rpm in the direction of rotation (D) 1500 rpm in the opposite direction of rotation