Final answer:
The correct verb phrase to complete the sentence is 'ha tenido'.
Step-by-step explanation:
The correct answer is A. ha tenido.
In this sentence, the verb phrase should agree with the subject, which is 'Carolina y mi hermana'. Since the subject is third person singular, the correct verb form is 'ha tenido'.
For example, if we were talking about 'yo' (I), the correct verb phrase would be 'he tenido'. But in this case, the subject is 'Carolina y mi hermana', so we use 'ha tenido'.
Learn more about Completing a sentence with the correct verb phrase in Spanish