which one of these is not a physical change?

In chocolate buring,it's heated so that the shpae of it changes but the structure of molecule doesn't change.This is physical change.
因为巧克力融化不涉及分子变化,只是物理形态的变化.
In paper buring,we know that the paper is made from wood,which consists of carbon,turns into carbon dioxide----and the form is from solid to gas.This is chemical change.
而纸张的燃烧,通常伴有其中以碳为主的物质结合氧气生成碳氧化合物的过程,所以说这是化学变化.