Question 18.

We can make a direct inference based on the following excerpt from the fourth paragraph: ["...This led Le Boeuf and his collaborator, Lewis Petrinovich, to deduce that the dialects were, perhaps, a result of isolation over time, after the breeding sites had been recolonised. For instance, the first settlers of Año Nuevo could have had, by chance, calls with low pulse rates. At other sites, where the scientists found faster pulse rates, the opposite would have happened—seals with faster rates would have happened to arrive first..."]

Based on the above information, the only reason behind the call pulse rate of male northern elephant seals in the southern rookeries being faster would be because the male northern elephant seals of Isla Guadalupe with faster call pulse rates might have been the original settlers of this region. Option A correctly highlights this reason and is, hence, the correct answer.