Final answer:
The dialogue reflects Mildred's concerns about the societal consequences of having books in 'Fahrenheit 451' and her fear related to potential material loss, which makes option a: Mildred to Montag about him having books, the correct choice.
Step-by-step explanation:
The excerpt "He might come and burn the house and the 'family'. That's awful! Think of our investment. Why should I read? What for?" is a dialogue that portrays Mildred's fear of the societal consequences of having books in Ray Bradbury's dystopian novel "Fahrenheit 451". In this society, books are banned, and the ownership of them can lead to the burning of one's home by the firemen, who are in charge of burning books. The character Mildred is concerned about the material loss and the investment she and her husband have made in their home, which could be destroyed if it is found that they own books. Therefore, this dialogue best matches option a: Mildred to Montag about him having books, as it reflects her concern about the repercussions of her husband Montag's interest in reading.