Which statement is most appropriate? 

Do we need to mistrust everyone and everything?: Testing applies the principle of asking what, where, when, and why, which is ingrained into the auditor as part of training and experience. 

Do we need to mistrust everyone and everything?: Testing applies the principle of asking what, where, when, and why, which is ingrained into the auditor as part of one's intuition. 

Do we need to mistrust everyone and everything?: Testing applies the principle of asking what, where, when, why and who should be blamed, which is ingrained into the auditor as part of training and experience. 

We need to mistrust everyone and everything: Testing applies the principle of asking what, where, when, and why, which is ingrained into the auditor as part of training and experience.