The correct answer is option 'C', the Treaty of Yandabo.

The First Burmese War was fought between the British East India Company and the Burmese Empire from 1824 to 1826. It was a result of British expansionist policies in Southeast Asia and conflicts over trade and territory.

Here is a detailed explanation of the Treaty of Yandabo and its significance in marking the end of the First Burmese War:

1. Background of the war:
- The British were expanding their influence in Southeast Asia and sought to establish control over Burma (now Myanmar) to secure their trade interests in the region.
- The Burmese Empire, ruled by King Bagyidaw, resisted British encroachment and maintained a policy of isolationism.

2. British invasion of Burma:
- In 1824, the British East India Company launched a military campaign to seize control of Burma.
- British forces quickly captured several key Burmese territories, including Rangoon (now Yangon).

3. Progress of the war:
- The Burmese initially put up a strong resistance but were eventually overwhelmed by the superior British military tactics and firepower.
- British forces advanced further into Burma, capturing important cities such as Prome and Ava.

4. Negotiations and the Treaty of Yandabo:
- As the Burmese realized their defeat was imminent, they sought peace negotiations with the British.
- The negotiations took place in the village of Yandabo, located near Ava, the capital of Burma.
- The Treaty of Yandabo was signed on February 24, 1826, between General Sir Archibald Campbell representing the British and Burmese representatives led by Governor-General Maha Min Hla Kyaw Htin.

5. Key provisions of the treaty:
- The treaty recognized the British control over Assam, Manipur, Arakan, and Tenasserim, which they had captured during the war.
- Burma agreed to pay a large indemnity to Britain, which caused significant financial strain on the Burmese Empire.
- The Burmese were also forced to cede the territories of Assam, Manipur, and Arakan to the British.

6. Significance of the Treaty of Yandabo:
- The treaty marked the end of the First Burmese War, establishing British dominance in Burma.
- It led to significant territorial gains for the British and expanded their control over Southeast Asia.
- The war and the subsequent treaty had a lasting impact on Burma, leading to political and economic changes as it came under British influence.

In conclusion, the Treaty of Yandabo marked the end of the First Burmese War, with the British securing major territorial gains and establishing their dominance in Burma.