How much diameter of pellet feed is the best starting feed for ducklings, which is beneficial to ducklings feeding.( ) A: 0.2-0.3cm B: 1-2cm C: 0.5-1cm D: 0.4-0.6cm

A behavioral ecologist is studying the behavior of ducks. Right after hatching, the ducklings are shown a large moving object, as well as the first few days after hatching. The ecologist notices that the ducklings are following the object wherever the ecologist moves that object. Which of the following behaviors would the ecologist suggest is responsible for the action of the ducklings? A: altruism B: imprinting C: fixed action pattern D: operant conditioning