Answer: Option C.
Step-by-step explanation:
Middle adulthood (or midlife) refers to the period between the age of 45 to 65 years.
Middle adulthood is is a stage which is hard to define because there are few variations in attitudes and behaviors exist from early adulthood.
There are several biological changes during this age which affects attitudes and behaviors of an individual. Physical changes involves aging which is inevitable; cognitive changes involves decline in intelligence and continued its descent; and great emotional upheaval, anxiety, and drastic changes in behavior with psychological changes.
Hence, the correct option is C.