Final answer:
The socioemotional selectivity theory states that an increased social network and expanded social activities contribute to older people's appreciation for life and mixed emotional states.
Step-by-step explanation:
According to the socioemotional selectivity theory, what increases older people's appreciation for life and gives rise to mixed emotional states that have a poignant quality is d) An increased social network and expanded social activities.
The socioemotional selectivity theory suggests that as people age, their focus shifts from acquiring material possessions and long-term career planning to prioritizing emotional goals and maintaining meaningful social connections.
Older people tend to have a limited time perspective, which leads them to appreciate life more and experience mixed emotional states that have a poignant quality.
One aspect of positive aging is believed to be social connectedness and social support, as older adults may have a smaller social network but maintain closer relationships.