Without evaluating the quality of the drawing, the obvious problem is the inclusion of your watermark.
In my opinion, the flecked green background is unsuitable for vector graphic use. I would not buy it. I prefer to buy vectors on a plain white background so I can use the graphic in commercial projects.
Also as @Jill_C said, watermarks, signatures and date & time stamps are not allowed on submitted artwork.
Read the DOs & DON'Ts in your Stock Contributor's Guide for more details.