The fourth pattern of the C Major scale uses the E shape open chord. When looking at the open E chord the root notes are on the top and bottom open E strings and the 2nd fret D string.
E
Reminder: The notes used in the C Major scale are C D E F G A B, there are no sharps or flats in the C Major scale.
If we take a look at the scale on the fretboard, you will see something like the following pattern… the root notes are marked with the “X“…
| | $1.7.$3.7.$4.7.$5.7.$6.7 | $1.X.$2.8.$5.8.$6.X | $3.9.$4.9 | $1.10.$2.10.$3.10.$4.X.$5.10.$6.10 |
Note: In the diagram above it’s the fret numbers that are indicated not the scale degrees, and it isn’t the way you would normally write out a scale using TAB, it’s just to illustrate the fingering pattern of the scale. 
When playing this scale on the guitar, I normally start on the lowest pitch root note, 6th string 8th fret, and play up to the highest pitch note of the scale, 1st string 10th fret, which is a D.
| $6.8 10 $5.7 8 10 $4.7 9 10 $3.7 9 10 $2.8 10 $1.7 8 10 |
Descending back to the lowest pitch note of the scale, the B on the 7th fret 6th string, then back up in pitch to the C root note on the 8th fret 6th string.
| $1.10 8 7 $2.10 8 $3.10 9 7 $4.10 9 7 $5.10 8 7 $6.10 8 7 | $6.7 8 |