Explanation:

Here’s how this breaks down:

- Option 1: 18th July – That’s the correct date. International Nelson Mandela Day is celebrated each year on July 18th to honor Mandela’s birthday and his contributions to peace and freedom.

- Option 2: 12th July – That date has no connection to Nelson Mandela Day or any major global event linked to him.

- Option 3: 11th July – This isn’t correct. July 11 is observed for World Population Day, not related to Mandela.

- Option 4: 10th July – Again, this one doesn’t relate to Mandela Day at all.

So to sum it up:

The right answer is Option 1: 18th July.