Final answer:
The example given describes the convoy model of social support.
Step-by-step explanation:
Alice, Jane, Lois, and Sandra who have been friends since grade school and have supported each other through various life events are an example of the convoy model of social support. This model suggests that social relationships accompany us throughout our lives and provide a protective layer of support. The convoy model posits that everyone has a personal network of family, friends, and acquaintances that moves with them through life, providing support during both good and challenging times.