High-level grafting: A method of cultivating large seedlings by grafting the branches or buds of ornamental trees on a large-sized rootstock to achieve rapid formation of a crown. It is now extended to enrich the economic construction of relatively high-level and higher-quality personnel. And the main battlefield of social development, to achieve the combination of high-level talents and grass-roots organizations, high-quality professional talents and the working masses. Based on the above definitions, which of the following are most suitable for high grafting? ['Young professional and technical personnel in the organization system of a provincial health department come to work with academicians.', 'A provincial science and technology department organized a senior engineer to take a post in a technology management position in a mountain science and technology enterprise.', 'Company A signs a cooperation agreement with Company B, and Company B sends a technician to Company A to serve.', 'Professor Zhang, a biotechnology patentee, resigned from his teaching post and set up a business in the mountainous area.']