The correct option is E No error
In option A, 'have' denotes possession of assets by the plural noun 'men', hence it's grammatically correct and has no error. In option B a comparison is made between the assets of the men in America with the assets of the poorest countries, hence option B is grammatically correct and has no error. In option C the adjective 'combined' emphasizes on the overall assets of the poorest countries, it is grammatically correct and has no error. 'Of' is expressing the relation between one part (sixty poorest countries) and the whole world,it refers to the 60 countries that are a part of the world. Hence option D has no error, which leaves us with the correct option i.e., option E.