Both are viable and even muting with the right hand would be a possibility depending on where you put that open string in the rythm.
I usually try to do it with the finger I play the next note with if it’s only a string crossing and not a complete jump over one string so I guess in this case I would roll my index over/have it relatively flat so it mutes the higher strings.
Did you see Joshs recent video about muting? I have nothing to add to that
