Answer: The sentence that contains an action verb is A. "My sister lost her computer yesterday", while the sentence that contains a linking verb is B. "Her shoes look really comfortable".
Explanation: An action verb is a verb that indicates a physical or mental action. Moreover, it expresses the type of action that the subject is carrying out. The only sentence that contains an action verb is A. "My sister lost her computer yesterday" since "lost" is expressing an action performed by "my sister". On the other hand, linking verbs are verbs that connect the subject to another element that provides additional information about this subject. In that way, a linking verb does not express an action. The only sentence that includes a linking verb is B. "Her shoes look very comfortable" since "look" is only establishing a relationship between the subject "her shoes" and "very comfortable".