The correct answer to this open question is the following.
Martin Luther King Jr. showed incredible persistence throughout his life. The example I choose to describe is the moment Dr, Martin Luther King Jr. was sent to prison in Birmingham, Alabama. My explanation is this.
Dr. King had been invited to Birmingham, Alabama in April 1963, and was jailed by the city police for leading non-violent demonstrations in downtown Birmingham. This part of the country had been one of the toughest places for African Americans.
As the leader of the Civil Rights movement, Dr. King knew the risks of visiting Birmingham and organize demonstrations. However, he had the courage to do it.
Once in jail, he wrote the famous and inspirational letter known as "Letter From Birmingham Jail."
This shows his incredible persistence throughout difficult moments, and he had many.