Final answer:
The question pertains to Physics and concerns the minimum possible speed of an electron, which requires further context about the electron's situation to accurately determine.
Step-by-step explanation:
The question involves calculating the minimum possible speed of an electron when it is influenced by magnetic and/or electric fields. Using physical constants such as Planck’s constant (h), the charge of the electron (e), and the mass of the electron (m), one could establish an equation based on the context of the problem, which is not fully described in the question. However, without additional information or a specific context provided, it's not possible to pinpoint which of the given formulas is correct for calculating the minimum speed of an electron.