A network engineer is tasked with implementing a cost-effective solution for connecting multiple sites that are geographically dispersed. The solution needs to provide a segregated wavelength for each site's data to minimize the crosstalk and maximize bandwidth. They decide to use an optical transmission technique that leverages different wavelengths of light for each signal. Which multiplexing technique should the engineer consider for this scenario?
Frequency Division Multiplexing (FDM)
Dense Wavelength Division Multiplexing (DWDM)
Coarse Wavelength Division Multiplexing (CWDM)
Time Division Multiplexing (TDM)