The correct answer is option 'D': Decreases the leadership quality among children.

Environmental education at the primary level aims to foster a sense of responsibility and respect for the environment among children. It encourages students to understand the interdependence between humans and nature, and promotes sustainable practices. The teaching of environmental education at the primary level supports various aspects of a child's development, such as social development, creativity, and improving the retention period of acquired concepts. However, it does not decrease the leadership quality among children.

Supports social development and peer learning:
- Environmental education at the primary level emphasizes the importance of collaboration, teamwork, and effective communication.
- It encourages students to work together in groups, discuss environmental issues, and find solutions collectively.
- Through group activities and projects, students learn to respect and appreciate different perspectives, develop empathy, and enhance their social skills.

Appreciates the creative work of children:
- Environmental education encourages children to express their ideas, thoughts, and emotions through various creative mediums such as art, drama, and storytelling.
- It recognizes and values the creative work of children, fostering their imagination, self-expression, and problem-solving skills.
- By engaging in creative activities related to the environment, children develop a deeper understanding of ecological concepts and develop a sense of ownership and responsibility towards the environment.

Improves the retention period of acquired concepts:
- Environmental education at the primary level focuses on experiential learning, where students actively engage in hands-on activities and observations.
- This approach enhances their understanding and retention of concepts as they are directly involved in the learning process.
- By connecting classroom learning with real-world experiences, students are more likely to remember and apply their knowledge in practical situations.

Does not decrease the leadership quality among children:
- Environmental education, if properly implemented, can actually enhance leadership qualities among children.
- It encourages students to take initiatives, make informed decisions, and become responsible citizens.
- By involving children in environmental projects and activities, they develop leadership skills such as decision-making, problem-solving, and teamwork.

In conclusion, environmental education at the primary level supports social development, appreciates children's creativity, and improves the retention period of acquired concepts. However, it does not decrease the leadership quality among children; instead, it can foster and enhance their leadership skills.