Ans: A. Asymptomatic(Ref Paniker's 7/e p162, 6/e pg180, 210)Larvae of Ascaris, Hookworm and Strongyloides migrate through lung & various other tissues during their lifecycle.Larva migrans:Sometimes larvae appear to lose way & wander around aimlessly.Generally seen when human infection occurs with nonhuman species of nematodes.Ascaris:Pathogenic effects of larval migration due to allergic reaction & not larvae presence.Hence larvae's initial exposure usually asymptomatic.Except on very heavy larval load.Symptomatic conditions:Visceral larvae migrans is produced by infection with non-human nematodes.Le. Nematodes frequently infecting dogs & cats.Cause local alveolar hemorrhages.Symptoms during migration due to allergic reaction & significant only in massive infections.Clinical pneumonitis seen only in massive infections.Hence mostly asymptomatic.