A male jackdaw's courtship behaviour ios astonishingly human. All his movements are consciously strained and his proudly reared head and neck are permanently in a state of self-display. He provokes the other jackdaws continually if the female jacdaw is looking on and he purposefully becomes embroiled in conflicts with otherwise deeply respected superiors. About all, he seeks to impress his loved one with the possession of a potential nesting site, from which he derives all other jackdaws, irrespective of their rank.
The most important 'trick' of the jack to win his female is

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A. displaying his head and neck
B. to be like a human being
C. to become embroiled with other birds
D. to possess a place for building a nest