The correct answer is option 'D', the African National Congress (ANC). The ANC played a significant role in leading the struggle against policies of segregation in South Africa. Here is a detailed explanation of the answer:

1. Introduction to the African National Congress:
The African National Congress (ANC) is a political organization that was founded in 1912 in South Africa. It initially aimed to represent the interests of the African people and fight for their rights in a racially segregated society.

2. Early Years of the ANC:
In its early years, the ANC focused on issues such as land rights, labor rights, and political representation for Africans. However, as apartheid policies were introduced in the 1940s, the ANC shifted its focus towards actively opposing racial segregation.

3. Defiance Campaign and Freedom Charter:
In the 1950s, the ANC initiated the Defiance Campaign, which aimed to challenge unjust laws and discriminatory practices through nonviolent protests. This campaign saw mass civil disobedience, including acts such as sit-ins and boycotts.

In 1955, the ANC, along with other anti-apartheid organizations, adopted the Freedom Charter. This document outlined a vision for a democratic and nonracial South Africa, with equal rights for all citizens. The ANC played a central role in promoting the principles of the Freedom Charter.

4. Rivonia Trial and International Pressure:
The ANC faced severe repression from the apartheid government, including arrests and banning orders on its leaders. One notable event was the Rivonia Trial in 1963, where several ANC leaders, including Nelson Mandela, were charged with sabotage and conspiracy. The trial gained international attention and highlighted the ANC's struggle against apartheid.

5. Armed Struggle and International Solidarity:
As peaceful protests were met with violent repression, the ANC increasingly turned to armed resistance. It formed the military wing, Umkhonto we Sizwe (MK), to carry out acts of sabotage against key government installations. The ANC also received support from various countries and international organizations, which helped raise awareness about the apartheid regime's injustices.

6. Negotiations and the End of Apartheid:
In the 1980s, the ANC intensified its struggle against apartheid, leading to widespread protests and international sanctions against the South African government. Eventually, negotiations between the ANC and the apartheid government began in the early 1990s, leading to the eventual end of apartheid in 1994.

7. ANC's Role in Post-Apartheid South Africa:
Following the end of apartheid, the ANC emerged as the ruling party in South Africa. Nelson Mandela, a prominent ANC leader, became the country's first democratically elected president. The ANC has since played a crucial role in shaping South Africa's political landscape and addressing the challenges faced by the country.

In conclusion, the African National Congress (ANC) led the struggle against policies of segregation in South Africa. It played a pivotal role in mobilizing the African people, organizing protests, and advocating for equal rights. The ANC's fight against apartheid ultimately contributed to the dismantling of the segregationist regime and the establishment of a democratic South Africa.

African National Congress is the organisation led the struggle against policies of segregation in South Africa by Nelson Mandela after 28yrs of prison.