An alternating current (a.c.) generator is linked to an oscilloscope. The diagram illustrates the trace that appears on the oscilloscope screen. What possible angles could there be between the plane of the coil and the direction of the magnetic field at the instants shown by points 1, 2 and 3?
- A$1: 0^{\circ},\; 2: 90^{\circ},\; 3: 180^{\circ}$
- B$1: 0^{\circ},\; 2: 90^{\circ},\; 3: 270^{\circ}$
- C$1: 90^{\circ},\; 2: 180^{\circ},\; 3: 0^{\circ}$
- D$1: 90^{\circ},\; 2: 270^{\circ},\; 3: 0^{\circ}$