Answer:
3). Marriage difficulties adversely affect parent-child communication.
Step-by-step explanation:
The key idea that is communicated in the given excerpt is that how 'difficulties in a marriage unfavorably influence the communication between parent and child.' The author's experience reveals how the separation or break-up of parents leads the children into a state of detachment and isolation as they are left 'wounded.' Thus, the author says 'break-ups are wont to do' as the children have to bear situations like 'one-parent Saturday-afternoon' which are 'nevertheless interactable.' The kids are left with no time for interaction or communication with their parents which could allow them to have a wonderful family experience and therefore, leave them 'deserted' and prevent them from sharing their problems or experiences openly.