Introduction:
The concept of Human Development was introduced by Dr Mahbub ul Haq, making option B the correct answer. Dr Mahbub ul Haq was a Pakistani economist and international development expert who played a significant role in highlighting the importance of human development as a key measure of a country's progress.

Explanation:
What is Human Development?
Human development refers to the process of enlarging people's choices and freedoms to live a long, healthy, and fulfilling life. It focuses on improving people's well-being by addressing their basic needs, expanding opportunities, and enhancing capabilities.

Role of Dr Mahbub ul Haq:
Dr Mahbub ul Haq was a pioneer in the field of human development. He believed that traditional measures of development, such as GDP per capita, were inadequate as they did not capture the well-being of individuals. Therefore, he developed the Human Development Index (HDI) in collaboration with the economist Amartya Sen.

Human Development Index (HDI):
The Human Development Index (HDI) is a composite measure of human development that takes into account three dimensions: health, education, and standard of living. It is a more comprehensive measure than GDP per capita as it considers factors such as life expectancy, literacy rate, and gross enrollment ratio in addition to income. The HDI provides a broader picture of a country's development by focusing on the well-being of its people.

Impact and Legacy:
Dr Mahbub ul Haq's concept of human development and the HDI have had a significant impact on development discourse and policy-making. His work has influenced international organizations, governments, and scholars to shift their focus from economic growth alone to a more holistic approach that emphasizes human well-being. The HDI is now widely used as a measure of development, and it has helped to raise awareness about the importance of investing in health, education, and social welfare.

In conclusion, Dr Mahbub ul Haq introduced the concept of Human Development and developed the Human Development Index (HDI) to measure a country's progress beyond traditional economic indicators. His contributions have significantly influenced the field of development and have highlighted the importance of improving people's well-being and expanding their choices and freedoms.