Play the D on the 7th fret third string with your first finger and then the C two semitones down on the same string with your second finger, moving from the 7th position to the 4th. There are a number of things to note here:
Once you're comfortable with this one, and it may take a while, play the C with your third finger so that your shuffling back into the 3rd position. When you've got that down play it in the 2nd position with your little finger. You'll notice the lateral roll in the wrist more now and also the importance of keeping all of the strings equally accessible to your little finger.