Final answer:
The author expresses an affectionate tone in the excerpt from “Stray,” as suggested by the warm and endearing depiction of Mrs. Lacey's amused reaction.
Step-by-step explanation:
The tone best expressed by the author in the excerpt from “Stray” is b affectionate. The description of Mrs. Lacey's actions, such as smiling and shaking her head in a manner that suggests a warm sense of bemusement rather than disapproval or confusion, conveys a tone that is caring and endearing towards the character being observed. It implies a deep-seated fondness, possibly indicating that she finds the subject's actions or personality charmingly incomprehensible. The affectionate tone is highlighted by how Mrs. Lacey's behavior shows a gentle and affectionate perplexity, rather than any form of negativity or judgment.