The answer should be A, meaning books about art. Yes, you could specify which kind of art you're talking about, but it's not grammatically necessary, and there are plenty of books that are about art in general. A book 'of' art would be a book that actually contains works of art. Like a 'box of art' or a 'collection of art'. All of these sound a bit odd, because we don't usually talk about art the way we talk about, say, candy.

Depending on what is inside, both would be correct. If there is art in the books then "of" is correct, but we don't usually use "of" even when that is what the books contain. "On" would be better suited because here it means "concerning" or "about" and is thus more general and would include the contents of the books. "Of" in "a work of art" has a different meaning. The meanings of the small common words are illustrated in "keys to words", a picture dictionary of the small common words. http://www.keys2words.info/

Thanks for your comment, Schwein. Practicing grammar exercises is something that I do besides reading books and listening to podcasts. I am sure there must be a reason why grammar exercises exist. They help people pay more attention to the grammar. If you find grammar exercises easy and/or lack of practical sense, then you probably don’t need them, and that would be your personal preference, but what made you think you could decide what other people need or don’t need is something that I cannot comprehend. Although I wouldn’t say reading and listening are *better* than doing grammar exercises, I would definitely say they are *different.* When people read, they tend to focus on the ideas in the passages. They don’t stop and analyze the grammar line after line. Listening is quite similar in that regard, but it trains a person’s brain to recognize the sounds of spoken English. But still, thanks for the input.

I dont see any sense in doing such exercises = =. As a Chinese grown up in China, I totally get the idea of this question. Yes, generally speaking it should be on art, which quite similar to abt art. But, of art is also correct grammatically. I would say, if I were you, I will just ignor these exercises. Reading and listening would be more practical than doing these all-about-grammar games.