How many pens are there in his desk

Choose the letter A, B, C or D to answer these following questions

Bob is a student. This is his bedroom. He does his homework, play computer games and relax here. There is a desk, a chair, a wardrobe, a bed and a bookshelf in his room. The wardrobe is between the desk and the bed. There is a computer, ten books and five pens on his desk. There are some pictures of his family on the wall. He loves this room so much, so he cleans it regularly.

Question:How many pens are there in his desk?