Tricky question for a six year old but for a GCSE exam?

Constantly Furious reports that the following was a question on his daughter's GCSE chemistry exam:

'What fluid is used in the home for drinking and washing?

The possible answers - yes, of course this was multiple choice - were as follows:

Water, Copper, Salt or Soap?'

Tricky? Not really, no. Did any candidate get this question wrong? Is this question part if the exam to boost results? Does anyone believe that the last Labour government did not preside over a dumbing down of our education system?