Final answer:
The correct answer is C. leyó. The subject of the sentence is tu madre, and the verb that agrees with this subject is leyó which refers to your mother reading the newspaper.
Step-by-step explanation:
The correct answer is C. leyó. The subject of the sentence is tu madre, which means 'your mother' in English. The verb 'leyó' corresponds with the third person singular pronoun 'él/ella' in Spanish, indicating that your mother read the newspaper.
Learn more about Sentence structure in Spanish