Final answer:
The correct answer is C. "Ser" is used to describe origin.
Step-by-step explanation:
The correct answer is C. "Ser" is used, because the sentence describes origin. In this sentence, the phrase "I am from the United Kingdom" is expressing the speaker's nationality or country of origin, which is a permanent characteristic. The verb "ser" is used to express permanent states or characteristics. On the other hand, the verb "estar" is used for temporary states or location. For example, if the sentence was "I am in the United Kingdom," then "estar" would be used.
Learn more about Verb usage in Spanish