Which individual investigated several proposals to establish a Quality of Life index?

The correct choice stems from the contributions of Hornback, who played a significant role in exploring proposals for a Quality of Life index. This index is crucial for assessing the overall well-being and living conditions within a community, considering factors such as environmental quality, health, education, and economic opportunities. Hornback's investigations would have involved analyzing various aspects of life that contribute to an individual's quality, thus leading to a comprehensive understanding of community health and well-being.

The other individuals mentioned likely contributed to different fields or discussions that may not specifically pertain to the development of a Quality of Life index, making Hornback the most relevant figure in this context. The emphasis on Hornback's work illustrates the importance of having a structured approach to evaluate quality of life, a concept that helps inform public health policies and community planning.