The question asks to identify the Hindu Kingdom that was located on Sumatra Island. To answer this, we need to examine each option provided and determine its historical geographical location and religious affiliation.

Srivijaya: The Key Sumatra Kingdom

Srivijaya was a powerful and influential thalassocratic (maritime) empire that flourished in Southeast Asia, primarily on the island of Sumatra, from the 7th to the 13th century CE. Its capital was likely near present-day Palembang in Indonesia.

• Srivijaya was a major center for both Hinduism and Mahayana Buddhism. It was particularly known as a prominent Buddhist learning center, attracting monks and scholars from various parts of Asia, including China and India. However, it also deeply incorporated Hindu elements, making it an Indianized kingdom with significant Hindu influences.
• This kingdom controlled vital sea lanes, especially the Strait of Malacca, which was crucial for trade between India and China, thereby becoming a wealthy and influential regional power.
• Its strong connections with India brought significant cultural and religious influences, leading to its identification as an Indianized, and broadly, a Hindu Kingdom in the context of broader Southeast Asian history.

Khamboja: A Central Asian Connection

The term Khamboja (also spelled Kamboja) refers to an ancient kingdom or a group of clans located in parts of ancient India and Central Asia, specifically in regions that are now parts of Afghanistan, Tajikistan, and northern Pakistan. It was never situated on Sumatra Island or in Southeast Asia. Therefore, Khamboja is not the correct answer.

Champa: The Vietnamese Coastline

Champa was an Indianized kingdom that existed along the coast of what is now central and southern Vietnam. The Cham people, who inhabited this kingdom, were significantly influenced by Indian culture, including Hinduism (especially Shaivism) and later Buddhism. However, Champa was located on the mainland of Southeast Asia, not on Sumatra Island. Thus, this option is incorrect.

Annam: Northern Vietnamese Region

Annam is a historical name often used to refer to the central and northern regions of Vietnam. Throughout history, this area was under significant Chinese influence for centuries and later became a core part of the independent Vietnamese state. While it played a crucial role in Vietnamese history, Annam was a geographical and political region, not an independent Hindu Kingdom located on Sumatra Island. Its primary cultural and religious leanings were distinct from the Indianized kingdoms of maritime Southeast Asia like Srivijaya.

Identifying the Kingdom on Sumatra Island

To summarize the locations and characteristics of the kingdoms discussed:

Based on the historical evidence, Srivijaya is the only option that represents a powerful Hindu Kingdom (or a kingdom with significant Hindu influence) located on Sumatra Island.