Which SFP and media-type combination should you recommend for a high-speed 10-kilometer link between two Cisco MDS switches?

A.
4-Gbps-LW, LC SFP, 50/125-micron multi-mode media

B.
4-Gbps-LW, LC SFP, 62.5/125-micron multi-mode media

C.
4-Gbps-LW, LC SFP, 9/125-micron single-mode media

D.
4-Gbps-LW, LC SFP, 50/125-micron single-mode media