The sound made by a tailor bird is called "cheeup-cheeup-cheeup". Let's explore this answer in detail:

Identification of the sound:
The sound made by a tailor bird is a distinctive "cheeup-cheeup-cheeup" sound. This sound is often described as a repetitive and high-pitched call.

Reason behind the sound:
The tailor bird produces this sound primarily for communication purposes. The male tailor bird uses this call to attract and communicate with a potential mate during the breeding season. This sound serves as a way for the tailor bird to establish its presence and to indicate its availability for mating.

Unique characteristics of the sound:
The "cheeup-cheeup-cheeup" sound made by the tailor bird is unique and easily recognizable. It is a repetitive call that is often heard in the early morning or late evening when the bird is most active. The sound is relatively loud and can carry over a considerable distance, allowing the tailor bird to communicate effectively with other birds in its vicinity.

Comparison with other bird sounds:
While different bird species have their own unique calls, the "cheeup-cheeup-cheeup" sound made by the tailor bird can be distinguished from other bird sounds. For example, the hoot of an owl (option B) is a deep and resonant sound, while the call of a crow (option C) is a harsh and cawing sound. Similarly, the sound made by a dove (option D) is a soft and cooing sound. Therefore, the correct answer is option A, "cheeup-cheeup-cheeup".

Conclusion:
The tailor bird is known for its distinctive "cheeup-cheeup-cheeup" sound, which it uses for communication purposes, particularly during the breeding season. This sound is unique and easily recognizable, setting it apart from the sounds made by other bird species.

Answer is a