Final answer:
The sentence implies that Anna Sewell wrote only one novel, as it points out 'Black Beauty' as 'her novel', suggesting it is her sole literary work.
Step-by-step explanation:
The sentence 'Anna Sewell's concern about the treatment of horses inspired her novel, Black Beauty, about the life of a horse in nineteenth-century London.'
suggests that Anna Sewell wrote only one novel. This is because the sentence specifically mentions her novel 'Black Beauty,' which is well-known to be her only novel.
Furthermore, the use of the singular 'her novel' implies that it is her sole work in this genre. Therefore, the correct answer is A. *Anna Sewell wrote only one novel.*
The sentence suggests that Anna Sewell wrote more than one novel. The statement mentions her novel, Black Beauty, indicating that she has written at least one novel.
Therefore, option B, Anna Sewell wrote more than one novel, is the correct interpretation of the sentence.