When installing Fiber 2km in length in a campus environment,which ISL configuration is recommended?

A.
Two ISL’s using multimode fiber and Longwave GBIC’s

B.
Single ISL using multimode fiber and Longwave GBIC’s

C.
Single ISL using singlemode fiber and shrtwave GBIC’s

D.
Two ISL’s using singlmode fiber and Longwave GBIC’s