Final answer:
Option (a) νλ=c is the correct answer as it accurately reflects the relationship that the speed of light (c) equals the product of frequency (ν) and wavelength (λ).
Step-by-step explanation:
The question presents a formula relationship in the context of electromagnetic waves, specifically looking for the correct equation that represents the relationship between the frequency (ν), wavelength (λ), and the speed of light (c).
The correct relationship is given by the equation c = νλ, where c is the speed of light, ν is the frequency, and λ is the wavelength. Based on the options provided, option (a) νλ=c is the correct one, fitting the relationship that the speed of light is equal to the product of the frequency and the wavelength of the electromagnetic wave.