Final answer:
Nelson Mandela's reference to South Africa as the 'skunk of the world' alludes to the international isolation and trade boycotts the country faced during apartheid, which B) many countries refused to trade with South Africa when they oppressed their citizens, best explains.
Step-by-step explanation:
When Nelson Mandela mentioned that South Africa will never again experience the indignity of being the skunk of the world, he was referring to the period during which South Africa was internationally ostracized due to its apartheid policies. The phrase 'skunk of the world' best explains that many countries refused to trade with South Africa as a result of its oppressive systems against the non-white population, essentially making South Africa a pariah state in the global community.
Throughout the apartheid era, South Africa faced international condemnation and economic sanctions, particularly in the 1980s, when the divestment movement and United Nations resolutions called on countries and personalities to partake in a cultural, economic, and political boycott. This international pressure, alongside the internal struggle led by groups such as the African National Congress (ANC), eventually contributed to the end of apartheid, ushering in a new era with the election of Nelson Mandela as president in 1994.