Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the option that best fits each of the numbered blanks from 18 to 22.

Humanoid robots have been a fascinating topic in both science fiction and reality. A prominent example is "Alexa", a social robot ___(1)___. Alexa's primary goal is to serve as a home assistant, capable of holding conversations, answering questions, and controlling smart devices. ___(2)___ . Since its launch, Alex has received multiple upgrades, allowing it to recognize emotions, improve its responses, and personalize interactions.
Alexa's design was inspired by the technological advancements in AI and machine learning. The incorporation of AI and machine learning greatly enhanced Alexa's capabilities. These advancements have helped to create a more responsive and adaptive system ___(3)___ .
Alexa's advanced AI features include speech recognition and emotion analysis, making it an ideal home assistant. ___(4)___. Moreover, Alex is able to adapt to new information. which also plays a vital role in how effectively Alex interacts with users.
The development of Alex required the combined efforts of AI researchers. engineers, and developers from multiple fields, including robotics, computer science, and cognitive science. ___(5)___ . Alex's continual improvement and adaptability make it a leading example of the future potential of AI-integrated technology.