The correct answer is D.) We loved reading In Search of Our Mothers’ Gardens by Alice Walker.
Explanation: The only word that should not be capitalized in the book title is the preposition word "of"; prepositions or conjunctions are not capitalized unless they contain five letters or more, or they are the first or last words of a book title.
Example of a conjunction that has five or more letters: The Light Between the Oceans
Example of a preposition that is less that five letters, that is the first word of the title: Of Mice and Men