The study examining infants' ability to do simple arithmetic that showed infants one or two dolls and then either added or subtracted a doll from behind a screen demonstrated that infants were surprised in which of these scenarios? Scenario A: A doll is placed behind a screen where another doll was initially present, and lowering of the screen reveals a single doll. Scenario B: A doll is removed from behind a screen where two dolls were initially present, and lowering of the screen reveals a single doll. Scenario C: A doll is placed behind a screen where another doll was initially present, and lowering of the screen reveals two dolls. Scenario D: A doll is removed from behind a screen where two dolls were initially present, and lowering of the screen reveals two dolls.