The correct description of Nelson Mandela is:
Mandela was a nonviolent activist and leader in the anti-apartheid movement. He was active in the ANC, spent several decades in prison, and was elected president of South Africa in the first election in which Black and mixed-race South Africans were able to vote freely.
While Mandela initially sought nonviolent means to achieve change, he eventually endorsed armed resistance due to the oppressive nature of the apartheid regime. However, he is primarily recognized for his efforts toward reconciliation and peaceful transition to democracy.