Final answer:
The nurse would expect to observe the infant rolling to their back from a prone position at the age of 5 months during a well-baby checkup.
Step-by-step explanation:
Based on the provided information, the nurse would expect to observe the infant rolling to their back from a prone position (option C) at the age of 5 months during a well-baby checkup. Rolling from front to back typically occurs around 2 months, while sitting without support and transferring objects from hand to hand usually happen around 6 months. Stranger anxiety, exhibited as signs of fear towards unfamiliar people, typically appears around 7 months.