Difference between a closed and an open group

What is the difference between a closed and an open group and what are some advantages and disadvantages for each?
What are a few methods you might use in recruiting members?
What issue would you want to explore during a pre-group interview?
You have a candidate that is insisting on becoming a member and won’t take no for an answer. How would you handle telling them that they are not a good fit for your group?

200 words