【英语】ItwasinAtlanta______nearlyhalfthepopulationwere……ItwasinAtlanta______nearlyhalfthepopulationwereblack______oneofthegreatleadersoftheCivilRightsMovement,Dr.MartinLutherKing,Jr.wasborn.A.that；thatB.tha

　　【英语】ItwasinAtlanta______nearlyhalfthepopulationwere……

　　ItwasinAtlanta______nearlyhalfthepopulationwereblack______oneofthegreatleadersoftheCivilRightsMovement,Dr.MartinLutherKing,Jr.wasborn.

　　A.that；that

　　B.that；where

　　C.where；that

　　D.where；where

　　帮我详细讲解一下这题为什么选“C”不选“B”?这些从句什么的我都不太懂.