How do I play this tab ?

![tab][1]

I confused since no fret number is written on the 3rd string, and I guess it's not an open string either. Do I pick those two (2 and 4) strings only?


What I did is just to strum those 3 strings with the middle one as open.


  [1]: https://i.sstatic.net/5QYZu.png