How do i tune the guitar d string to c?

Question

How do i tune the guitar d string to c?

Answer 1

detune the D string so it sounds the same as the5th string on the 3rd fret

Answer 2

You have to go down a whole step. You do this by loosening the string to where when you hold down the 7th fet of the D string it sounds like the 3rd string. Hope that helps.