Final answer:
A normal sign of involution during the postpartum period would be the uterine fundus being firm and midline. Involution refers to the uterus shrinking back to its pre-pregnancy size, and breastfeeding can assist this process.
Step-by-step explanation:
During the postpartum period, signs of normal involution in a client would include a uterine fundus that is firm and midline. Involution is the process by which the uterus returns to its pre-pregnancy size, and breastfeeding can facilitate this process. The other options provided: a) Increased abdominal circumference, b) Elevated blood pressure, and d) Vaginal bleeding exceeding a pad per hour are not indicators of normal involution and could suggest potential complications such as postpartum hemorrhage or preeclampsia.