SARS-CoV-2 virus (Covid-19) is a very contagious virus and most individuals infected by the virus show symptoms. However, some people infected with the disease do not show symptoms at all. These people are:

• A. Passive, symptomatic carriers.
• B. Passive, asymptomatic carriers.
• C. Active, symptomatic carriers.
• D. Active, asymptomatic carriers.
• E. b or c.
• F. c or d.

Answer: (D)

Verified step by step guidance

1. Step 1: Understand the definitions of carrier types in microbiology. A 'carrier' is an individual who harbors a pathogen and can potentially transmit it to others.
2. Step 2: Differentiate between 'active' and 'passive' carriers. Active carriers are those who are currently infected and can spread the pathogen, while passive carriers may carry the pathogen temporarily without being infected themselves.
3. Step 3: Understand the difference between 'symptomatic' and 'asymptomatic' carriers. Symptomatic carriers show symptoms of the disease, whereas asymptomatic carriers do not show any symptoms despite being infected.
4. Step 4: Apply these definitions to the SARS-CoV-2 context. Individuals infected with SARS-CoV-2 who do not show symptoms but can still spread the virus are considered 'active, asymptomatic carriers' because they are infected and capable of transmission without symptoms.
5. Step 5: Conclude that the correct classification for people infected with SARS-CoV-2 who do not show symptoms is 'active, asymptomatic carriers.'