Final answer:
An electromagnetic wave consists of vibrating electric and magnetic fields traveling together. It is generated when an electric charge oscillates, creating fields that are perpendicular to each other and can propagate through empty space at the speed of light. So the correct option is A.
Step-by-step explanation:
The item made up of vibrating electric and magnetic fields traveling together is A. An electromagnetic wave. When an electric charge moves, it generates both an electric field (E) and a magnetic field (B), which are perpendicular to each other. If the charge oscillates, like in an alternating current, an electromagnetic wave is propagated, comprising these self-propagating electric and magnetic fields. These waves can travel through a vacuum at the speed of light, approximately 3 × 108 m/s, and can also move through mediums like water and air, albeit at a slower pace. The strength of the magnetic field in an electromagnetic wave is related to the strength of the electric field by the equation B = E/c, where c is the speed of light.