Final answer:
EM waves are mostly scattered by objects that are about the same size as the wavelength of the wave, which results in resonances and enhanced scattering.
Step-by-step explanation:
Electromagnetic (EM) waves can be scattered when they encounter objects, and the degree of scattering generally depends on the characteristics of the object they interact with. Among the options provided, EM waves tend to be scattered the most by objects that are about the same size as the wavelength of the wave.
When the size of the scatterers is comparable to the wavelength of the EM wave, resonances occur that enhance scattering. This principle explains why the sky is blue since the molecules in the atmosphere have sizes comparable to the wavelength of blue light, leading to a more pronounced scattering of blue light over other colors with longer wavelengths.
Reflective objects would not scatter the waves but rather reflect them. Conductive materials can absorb EM waves and may re-radiate them, but this is not the same as scattering. Magnetic and liquid materials could potentially influence the propagation of EM waves, depending on their electrical properties, but as a general rule, the size of the object relative to the wave's wavelength is the most critical factor in determining scattering.