Double-blind techniques should be used whenever possible in scientific experiments. They help prevent the misinterpretations that often arise due to expectations and opinions that scientists already hold, and clearly scientists should be extremely diligent in trying to avoid such misinterpretations. Which one of the following most accurately expresses the main conclusion of the argument? ['It is advisable for scientists to use double-blind techniques in as high a proportion of their experiments as they can.', 'Scientists sometimes neglect to adequately consider the risk of misinterpreting evidence on the basis of prior expectations and opinions.', "Scientists' objectivity may be impeded by interpreting experimental evidence on the basis of expectations and opinions that they already hold.", 'Double-blind experimental techniques are often an effective way of ensuring scientific objectivity.']