How is it that the sound of music playing in a street can be heard many streets away despite the fact that there are many buildings and other structures obstructing the path of the sound waves? A. Sound waves transmit through the buildings and structures.
B. Sound waves can diffract around obstacles.
C. The sound waves are carried by the wind.
D. Sound waves interfere with other types of waves in order to transmit through barriers.

electromagnetic shielding is the practice of reducing the electromagnetic field in a space by blocking the field with barriers made of conductive or magnetic materials. shielding is typically applied to enclosures to isolate electrical devices from their surroundings, and to cables to isolate wires from the environment through which the cable runs. electromagnetic shielding that blocks radio frequency electromagnetic radiation is also known as rf shielding.

the shielding can reduce the coupling of radio waves, electromagnetic fields and electrostatic fields. a conductive enclosure used to block electrostatic fields is also known as a faraday cage. the amount of reduction depends very much upon the material used, its thickness, the size of the shielded volume and the frequency of the fields of interest and the size, shape and orientation of apertures in a shield to an incident electromagnetic

from wikipedia