The correct answer is: A. He said that he saw a book here.
The sentence “He said, ‘I saw a book here'” is in the past tense. This means that the action of seeing the book happened before the time of speaking. The word “here” indicates that the book was seen in a specific location. The word “saw” is the past tense of the verb “to see.” Therefore, the most likely interpretation of this sentence is that the speaker saw a book in a specific location at some point in the past.
Option B is incorrect because the word “there” does not match the word “here” in the original sentence. Option C is incorrect because the word “had” indicates that the action of seeing the book happened before some other event in the past. Option D is incorrect because the word “there” does not match the word “here” in the original sentence.