Here's a problem to solve: Cameron is shopping for a new desk. He wants to make sure the desk will fit in the corner of his room. When Cameron shops for the new desk, which of the following will best help him make sure that the desk will fit?

Among the 4 following options, which is the correct answer?

- A: a picture showing the carpet in his room
 
- B: a diagram of the measurements of his room
 
- C: a drawing showing how to put a desk together
 
- D: a list of tools he needs to put the desk together
 