The table below lists terminologies (column X) and concepts (column Y) related to ecological niche.

Column X		Column Y
A	Niche complementarity	i	Species distribution explained by trophic levels and biotic interactions.
B	Niche packing	ii	Tendency for coexisting species which occupy a similar position along at least one niche dimension.
C	Community niche	iii	Tendency for coexisting species to fill the available space along important niche dimensions.
D	Eltonian niche	iv	Composition of niches of all individual species niches that co-occur at the same site.

Which one of the following options represents the correct match between column X and column Y?