Sentence:  Examples are in public utilities , making military aircraft and accessories , or where the investment and risk for a <WSD>proprietorship</WSD> would be too great for a much needed project impossible to achieve by any means other than the corporate form , e. g. constructing major airports or dams . 
Meaning of the word marked with <WSD> tags:  an unincorporated business owned by a single person who is responsible for its liabilities and entitled to its profits