All etching tools are either pin-tipped or bladed. While some bladed etching tools are used for engraving, some are not. On the other hand, all pin-tipped etching tools are used for engraving. Thus, there are more etching tools that are used for engraving than there are etching tools that are not used for engraving. The conclusion of the argument follows logically if which one of the following is assumed? ['All etching tools that are not used for engraving are bladed.', 'No etching tool is both pin-tipped and bladed.', 'All tools used for engraving are etching tools as well.', 'There are as many pin-tipped etching tools as there are bladed etching tools.']