One Pocket Question

[DelaWho???]

When playing 1 pocket, if your opponent pockets a ball in your pocket, what is the rule?

1. Does it spot and the player lose a turn?

2. Does it stay down and count toward my score and the player lose his turn?

3. Does it stay down, count and he continues his turn?

4. Is it a foul?

We have been using option 2. What is correct?

 

[Mark V]

Option 2, unless while pocketing your ball, he scratches the cue ball off the table. In that case, that ball and one of his spots up.