Questions: According to the host, why is it important for even people who aren't showing symptoms to wear masks? A. Because many people who carry the virus don't show symptoms, but could still get others sick. B. Because people who who haven't had the virus should protect themselves even more from getting sick. C. Because asymptomatic carriers are more contagious than those who experience symptoms. D. Because wearing a mask is generally a good way to increase blood oxygen levels.

The answer is A: Because many people who carry the virus don't show symptoms, but could still get others sick.

Explanation for each option:

A. Because many people who carry the virus don't show symptoms, but could still get others sick.

• This is the correct answer. Asymptomatic carriers of a virus can still spread the virus to others, even if they do not show any symptoms themselves. This is why public health guidelines often recommend that everyone wear masks to reduce the transmission of the virus.

B. Because people who haven't had the virus should protect themselves even more from getting sick.

• While it is true that people who haven't had the virus should take precautions to avoid getting sick, this option does not address the specific reason given by the host, which is the potential for asymptomatic carriers to spread the virus.

C. Because asymptomatic carriers are more contagious than those who experience symptoms.

• This statement is not accurate. Asymptomatic carriers can spread the virus, but there is no evidence to suggest that they are more contagious than symptomatic individuals. The key point is that they can still spread the virus without knowing it.

D. Because wearing a mask is generally a good way to increase blood oxygen levels.

• This statement is incorrect. Wearing a mask does not increase blood oxygen levels. Masks are primarily used to reduce the spread of respiratory droplets that may contain the virus.

In summary, the correct answer is A because it directly addresses the importance of wearing masks to prevent the spread of the virus by asymptomatic carriers.