Laennec’s cirrhosis is caused due to
A. Virus
B. Bacterium
C. Protozoan
D. Metabolic disorder

Hint: Cirrhosis, which is also known as liver cirrhosis or hepatic cirrhosis, and end stage liver disease, is the impaired liver function which is caused by the formation of scar tissue due to the damage caused by liver disease, known as fibrosis. Tissue repair and subsequent formation of scar tissue occurs due to damage, which with time can replace normal functioning tissue and leads to the impaired liver function of cirrhosis.

Complete answer:
Option A Virus: A submicroscopic infectious agent that can replicate only inside of living cells of an organism is known as a virus. Cirrhosis is commonly caused by alcoholic liver disease, non-alcoholic steatohepatitis, chronic hepatitis B, and chronic hepatitis C. Virus causes both hepatitis B and C.
Hence option A is correct.
Option B Bacterium: The large group of single celled organisms which lacks a cell nucleus, reproduce by fission or by forming spores, and in some cases can be pathogenic and cause disease are known as bacterium. One of the most abundant lifeforms on Earth is the bacteria, and are mostly found in all living things and in most of the Earth's environments. Bacteria do not cause cirrhosis.
Hence option B is incorrect.
Option C Protozoan: The single celled microscopic animal of the kingdom Protista, which includes amoeba, flagellate, ciliate, or sporozoan are known as protozoan. Deadly human diseases caused by protozoan infection include African Sleeping Sickness, amoebic dysentery, and malaria. They do not cause cirrhosis.
Hence option C is incorrect.
Option D Metabolic disorder: When abnormal chemical reactions in the body disrupt the process of metabolism, metabolic disorder occurs. Cirrhosis is not caused by metabolic disorder.
Hence option D is incorrect.

Hence, Option A. Virus is the correct answer.

Note:
Early symptoms of cirrhosis include tiredness, weakness, loss of appetite, unexplained weight loss, nausea and vomiting, and discomfort at the right upper quadrant of the abdomen. Symptoms may include itchiness, swelling in lower legs, abdomen fluid buildup, jaundice, bruising easily. And development of spider-like blood vessels in skin as the disease worsens.