A
Rock accretions composed mainly of manganese, iron, nickel, copper, and cobalt.
B
Pure crystalline deposits of sodium chloride and lithium carbonate.
C
Fossilized organic coral reefs containing high concentrations of calcium carbonate.
D
Bituminous coal and petroleum hydrocarbon reservoirs trapped in sub-seabed sedimentary basins.
Correct answer: (a) Rock accretions composed mainly of manganese, iron, nickel, copper, and cobalt.
Explanation
Option A is correct because polymetallic nodules are rock accretions on the deep ocean floor composed mainly of manganese, iron, nickel, copper, and cobalt. Options B, C, and D misstate their geological composition.
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