phy electromagnetic wave

The correct statement is (3) only.

(1) is wrong. Consider sound wave, which is a mechanical wave. When it travels from water to air (two different medium), it bends towards the normal too. But it is not an electromagnetic wave.

So, refraction is only sufficient to tell whether it is a wave or not, but not the kind of wave.

(2) is wrong. Similarly, sound reflects when it meets a polished metal surface too. So, it is insufficient to tell.

(3) is correct. Between the Sun and the Earth, there is no any medium but vacuum. Only electromagnetic wave can travel in vacuum. So, this can tell light is an electromagnetic wave.