The Human Poverty Index (HPI) was introduced in the Human Development Report of the year 1997.

The Human Development Report (HDR) is an annual publication by the United Nations Development Programme (UNDP) that examines various aspects of human development worldwide. It provides insights into human well-being, progress, and challenges across different countries and regions.

The Human Poverty Index is a measure that goes beyond income-based indicators to assess the multiple dimensions of poverty. It takes into account factors such as access to education, healthcare, nutrition, and basic living conditions. The HPI provides a more comprehensive understanding of poverty by considering both income deprivation and social deprivation.

The HPI was first introduced in the 1997 Human Development Report as a new measure to complement the traditional income-based indicators of poverty. It aimed to provide a more nuanced perspective on poverty and to highlight the importance of addressing non-income dimensions of deprivation.

Therefore, the correct answer is option D: 1997.