Faraday's Law of Induction states that:

Faraday's Law of Induction specifically states that a changing magnetic field within a closed loop or circuit induces an electromotive force (EMF). This principle underlies the operation of many electrical devices, such as generators and transformers. The key concept is the relationship between magnetic fields and electric currents, emphasizing that it is the change in the magnetic field that is crucial. The law quantitatively describes how the induced EMF is proportional to the rate of change of the magnetic flux through the loop, exemplified by the formula EMF = -dΦ/dt, where Φ represents the magnetic flux.

This understanding is foundational in electromagnetic theory, illustrating why dynamic conditions—specifically changes—are necessary for induction to occur, rather than static magnetic situations or conditions. The options related to constant magnetic fields or the existence of electric charges without magnetic fields do not accurately reflect the essence of Faraday's Law, which focuses solely on the impact of changing magnetic environments. Therefore, choice B is the only one that encapsulates the core principle of induction as outlined by Faraday.