At what age is night-time control of the bladder and bowel normally attained?

Correct option is D

Night-time bladder and bowel control is typically developed by the age of 3 years. This milestone reflects maturation of the nervous system and the ability to recognize and respond to the need to urinate or defecate. While day-time control often appears earlier, night-time control takes longer due to deeper sleep patterns and limited awareness during sleep.
Explanation of options: (a) ✘ 6 years – This is beyond the typical developmental milestone for bladder control. (b) ✘ 1 year – Too early for most children; control is neurologically immature at this stage. (c) ✘ 2 years – Partial control may start, but complete night-time control is uncommon. (d) ✔ 3 years – Most children achieve reliable night-time bowel and bladder control by this age.