D. lactobacillus is the right answer
A. behavioral isolation is when the plant or animal acts a particular way to attract their counterparts, like mating rituals.
geographic isolation is the natural barrier preventing similar species from interacting. for example, Galapagos Islands are the only home of flightless cormorants because the islands are so far from any other land for them to invade.
Temporal isolation is when two of the same or similar species cannot reproduce as a result of mismatched sexual maturity.
B. the isolation of two frog species by mating call is behavioral isolation.
Probably the intertidal zone, as I reason the tides would affect life dramatically. High and low tide would affect land and ocean creatures in this zone too often where as the coastal and open oceans have constant properties.