A female cat in heat urinates more often and in many places.Male cats congregate near the urine deposits and fight with each other.Which of the following would be an ultimate cause of the male cats' response to the female's urinating behaviour?

A)The males have learned to recognize the specific odour of the urine of a female in heat.
B)When the males smelled the odour, various neurons in their brains were stimulated.
C)Responding to the odour means locating reproductively receptive females.
D)Male cats' hormones are triggered by the odour released by the female.
E)The odour serves as a releaser for the instinctive behaviour of the males.