The littoral and riparian zones are different because of option d. Riparian zones occur where water meets land, while littoral zones occur at depths of less than 15 feet.
In the case of riparian zones, it should be arise at the time when the water should meet the land.
On the other hand, littoral zones should be arise at the time when there is the depth of less than the 15 feet.
hence, the option d is correct.
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