Parents usually ask when their child can return to school after having chickenpox. The correct answer would be:

A. Returning to school solely based on a normal temperature is insufficient because the child can still spread the virus if lesions are not crusted. B. Waiting until lesions have completely faded is unnecessary; contagion risk ends when lesions are crusted over. C. The child is considered no longer contagious once all lesions have crusted. At this point, the virus is no longer easily transmitted to others, making it safe to return to school. D. The timing of 10 days after onset is variable and not a reliable indicator of non-contagiousness, as lesion progression differs among children.