The correct answer is option 'D' - 1990s.

Explanation:

Background:
The history of racial segregation and discrimination in South Africa dates back to the colonial era when the Dutch and British settlers implemented policies that favored white supremacy. The system of apartheid, which was officially introduced in 1948, institutionalized racial segregation and denied black people equal rights and opportunities.

Struggle against Apartheid:
Throughout the years, black South Africans and various anti-apartheid movements fought against the discriminatory policies of the government. They faced immense repression, including violent crackdowns, imprisonment, and even assassinations. The African National Congress (ANC), led by figures such as Nelson Mandela, played a crucial role in mobilizing the resistance against apartheid.

Key Events:
1. 1990: The first significant step towards equality came in 1990 when President F.W. de Klerk announced the unbanning of the ANC and other anti-apartheid organizations. This signaled the beginning of negotiations to dismantle apartheid and establish a new democratic South Africa.

2. 1994: The year 1994 marked a monumental milestone in South Africa's history. It was the year of the first multiracial democratic elections, in which all South Africans, regardless of race, were allowed to vote. Nelson Mandela, who had been released from prison in 1990, became the country's first black president.

3. 1996: The new democratic government took significant steps towards achieving equal citizenship rights for all South Africans. In 1996, the South African constitution was adopted, which enshrined fundamental rights and freedoms for all citizens, regardless of race.

4. 1998: The South African government also established the Truth and Reconciliation Commission (TRC) in 1995, which aimed to address the crimes and human rights violations committed during the apartheid era. The TRC provided a platform for victims to share their stories and for perpetrators to seek amnesty in exchange for truth-telling.

Conclusion:
In the 1990s, South Africa underwent a transformative period, transitioning from apartheid to democracy and granting equal citizenship rights to all its people. The end of apartheid and the establishment of a democratic government were significant achievements, but the effects of centuries of racial discrimination and inequality still persist in South Africa today.