Chord Csus2 notes: C, D, G, C and G. You should not play the 6th string.
The guitar strings 4(D) and 3(G) are left open.
Csus2 - C suspended 2nd guitar chord is often noted with non-standard names like C5add2, C2(no3) or C2. Sometimes it's referred to as Cadd9(no3).
1(C), 2(D), 5(G).