Choose the correct option.

If anyone were to tell you that animals had some kind of sixth ... that allowed them to predict when a disaster was about to happen, would you think you were being teased? Many people would, but an increasing ... of animal behaviour experts are beginning to suspect that animals have some sort of ability to sense impending danger.
As an example ... this, it has been reported that on the morning of the catastrophic tsunami in Thailand, a ... of elephants that were feeding on a beach near the village of Bang Koey seemed to be aware that something terrible was about to occur. To the surprise of the villagers who were in ... of them, the elephants suddenly stopped feeding, looked at the sea and then began running ... higher ground. Mystified by this peculiar behaviour, many of the villagers chose to follow them, a decision that probably saved their lives.
It wasn’t long afterwards, only minutes in fact, that the huge ... swept in from the sea destroying everything in its path.