Read the following passage and answer by choosing the right answer.

Dolphins are regarded as the friendliest creatures in the sea, stories of them helping drowning sailors have been common since Roman times. The more we learn about dolphins, the more we realise that their society is more complex than people previously imagined. They look after other dolphins when they are ill, care for pregnant mothers and protect the weakest in the scientists have community, as we do. Some suggested that dolphins have a language but it is much more probable that they communicate with each other without needing words. Could any of there mammals be more intelligent than man? Certainly the most common argument in favours of man's superiority over them, is that we can kill them more easily than they can kill us is the least satisfactory, on the contrary, the more we discover about these remarkable creatures, the lees we appear superior when we destroy them.

The fact that the writer thinks that we can kill dolphins more easily than they can kill us ............