Final answer:
The phrase 'Lo compré' correctly completes the second sentence.
Step-by-step explanation:
The correct phrase to complete the second sentence is Lo compré. The phrase 'Lo compré' means 'I bought it' in English. Since 'regalo' (gift) is masculine and singular, we use the masculine singular pronoun 'lo' to refer to it. Therefore, the correct answer is B. Lo compré.
Learn more about Spanish pronouns