Well, I voted for the first option because I'm an only child and grew up with both of my parents. My parents are still married and both have college degrees and my Mom when to graduate school in philosophy for a time, but did not finish.
I actually wouldn't say that I personally identify with any of the family dynamics in BBM.
While I was an only child like Jack, my parents were absolutely not abusive. In fact, my parents strongly dissapprove of physical discipline. And, I have a strong relationship wth both parents (the dynamics in my relationships with my Mom and Dad are different in each case... but strong in equal measure).
There was a brief time when I was about 8 when my parents were clearly having some marital difficulty and my Dad went and stayed with a friend for a couple weeks. I honestly can say that I don't really know what was going on with them to cause that brief rift. But, they worked things out in a relatively short time.
The thing I identify with most is Ennis's behavior as a "loner" as an adult. And, in recent months I feel like this identification is actually increasing for me. I obviously don't have a family of my own and don't really expect to have one.
When I was younger (in college and grad school) I was a lot more social and might have identified more with Jack back then.