Books that have been returned to the library must be sorted before they are put back on the shelves. First, look at the stickers on the back edge of the books. Put books with a yellow dot above the label on the green cart. These new books will go on special shelves near the checkout desk. Books without a yellow dot go on gray carts.

Next, the books on each cart must be sorted by the label code. Codes always start with a letter of the alphabet, and most books have two letters in the code. Put all books in alphabetical order. For example, books with the letters PN go before books with the letters PV.

If several books have the same letter code, then use the number code on the label just below the letters. For example, a book coded PN 210 goes before a book coded PN 225.

When all the books on the carts are sorted, start putting them in the appropriate places on the shelves.

You work at the library. According to these instructions, where should you put a book coded PN 225 that does NOT have a yellow dot above the sticker?

Before a book coded NP 220
Before a book coded NP 230
Before a book coded PN 220
After a book coded PN 220
After a book coded PN 230