How many days is chicken pox contagious for?

Chickenpox, caused by the varicella-zoster virus, is typically contagious from about one to two days before the onset of the rash until all the blisters have formed scabs. This usually falls within a span of approximately 5-7 days, but the recognized period during which a person can transmit the virus is generally up to about 10 days after the rash appears.

Considering the choices given, while 11 days might seem slightly longer than the typical contagion window, it reflects the extended duration certain individuals might still carry the virus in their body and possibly transmit it. Thus, this choice captures the general understanding of the contagious nature of chickenpox, which aligns with common guidelines in public health regarding infectious diseases.

The choice indicating 10 days, while reasonable, does not encompass the entirety of the potential contagion window. The other options of 5 days and 15 days are respectively too short and too long compared to medical consensus. Hence, the choice mentioning 11 days is the most comprehensive in covering the full range of contagion related to chickenpox.