The correct answer is option 'D' - The Shanghai Massacre.

Explanation:

The Shanghai Massacre, also known as the April 12 Incident, was a significant event in 1927 that marked a turning point in the Chinese Revolution, leading to a split between the Nationalists and Communists. Here is a detailed explanation of this event:

1. Background:
- The Chinese Revolution aimed to overthrow the ruling Qing Dynasty and establish a republican government.
- After the revolution succeeded in 1911, the Nationalist Party (Kuomintang or KMT) emerged as a dominant political force.
- The Communist Party of China (CPC) was founded in 1921 and gradually gained influence.

2. Alliance between Nationalists and Communists:
- In the early 1920s, the KMT, led by Sun Yat-sen, formed an alliance with the CPC to work together against warlords and foreign influence.
- This alliance was known as the First United Front and aimed to unite all revolutionary forces in China.

3. The Northern Expedition:
- In 1926, the KMT launched the Northern Expedition to overthrow the warlords and reunify China.
- The CPC actively participated in this military campaign, contributing troops and gaining support among the peasants.

4. The Split:
- As the Northern Expedition progressed, tensions between the Nationalists and Communists grew.
- The Nationalists, under Chiang Kai-shek's leadership after Sun Yat-sen's death, became increasingly anti-communist.
- Chiang saw the CPC's growing influence as a threat to his power and the interests of the KMT.

5. The Shanghai Massacre:
- On April 12, 1927, Chiang Kai-shek ordered a violent purge of the CPC members in Shanghai.
- Thousands of Communists and suspected sympathizers were arrested, executed, or forced to flee.
- This marked the beginning of a widespread anti-communist campaign by the Nationalists.

6. Consequences:
- The Shanghai Massacre shattered the First United Front and led to a split between the Nationalists and Communists.
- The CPC was forced to retreat to rural areas and adopt guerrilla warfare tactics.
- This event set the stage for the Chinese Civil War between the Nationalists and Communists, which lasted until 1949.

In conclusion, the Shanghai Massacre in 1927 marked a turning point in the Chinese Revolution by leading to a split between the Nationalists and Communists. It shattered the alliance between the two parties and set the stage for the long and bloody Chinese Civil War.