After a terrorist attack in Brussels, Sharon disagrees with others and believes that intelligence agencies could not have foreseen the event. Sharon is avoiding an error in thinking known as:

- Hindsight bias.

Explanation:

'Hindsight bias' is described as the general human proclivity to overvalue their ability to perceive or anticipate the outcome of an event (after the event) as more predictable or foreseeable than it actually is. In such a bias, people tend to show that they were quite certain of the outcome that has been created by the event.

In the given example also, Sharon's disagreement with the others reflect her 'hindsight bias' as she is excessively valuing her potential to have foreseen the consequence of the attack (that originally was unpredictable) which is reflected by her belief that 'intelligence agencies could not have foreseen the event'. Thus, 'hindsight bias' is the answer.