Pakistan’s population constitutes approximately 2.65% of the world’s total population according to recent UN estimates. This makes Pakistan one of the most populous countries globally. Population statistics are important for planning economic development, resource allocation, and policy-making. A large population also presents both opportunities and challenges, including workforce potential and pressure on resources. Thus, 2.65% is the correct answer based on recent demographic data.

The Rio Earth Summit, formally called the United Nations Conference on Environment and Development (UNCED), was held in June 1992 in Rio de Janeiro, Brazil. It was one of the largest international gatherings focused on environmental issues and sustainable development. The summit produced several key outcomes, including Agenda 21, a comprehensive plan for sustainable development; the Rio Declaration, which outlines principles for environmental protection; and major conventions on climate change and biodiversity. These agreements laid the foundation for modern environmental policy and global cooperation. The summit emphasized the concept of sustainable development, which balances economic growth with environmental protection. It highlighted the responsibility of nations to protect natural resources while promoting development. Other dates listed are incorrect because the conference specifically took place in June 1992. It remains a landmark event in environmental history. Thus, June 1992 is the correct answer, representing a pivotal moment in global environmental awareness and policy-making.

Parthenocarpy is the development of fruit without fertilization, resulting in seedless fruits. This phenomenon can occur naturally or be induced artificially using plant hormones. Common examples include bananas and seedless grapes. These fruits are commercially valuable because they are easier to eat and often preferred by consumers. In normal fruit development, fertilization triggers seed formation. In parthenocarpy, this step is bypassed, but fruit growth still occurs. Other options are incorrect because parthenocarpy specifically refers to seedless fruit production. Thus, seedless fruit is the correct answer. This concept is important in botany and agriculture, especially in improving crop quality and market value.

Kurt Waldheim served as the fourth Secretary-General of the United Nations from 1972 to 1981. The Secretary-General is the chief administrative officer of the UN and plays a key role in international diplomacy. Waldheim’s tenure focused on global peace efforts and conflict resolution during the Cold War period. His role involved mediating disputes and representing the UN on international platforms. Thus, he is ranked as the 4th Secretary-General, making option D correct.

Amjad Hussain Sial from Pakistan served as the Secretary-General of SAARC (South Asian Association for Regional Cooperation). SAARC is a regional organization that promotes economic and cultural cooperation among South Asian countries. The Secretary-General is responsible for coordinating activities, implementing decisions, and facilitating cooperation among member states. The position rotates among member countries. Antonio Guterres is the UN Secretary-General, not SAARC. Ajay Bisaria is an Indian diplomat, and Arjun Bahadur Thapa is a former SAARC Secretary-General. Thus, Amjad Hussain Sial is the correct answer in this context, reflecting leadership within regional cooperation frameworks.