Correct Answer: 1997

Solution : The correct option is 1997.

The H5N1 virus, generally known as avian influenza (bird flu), is a kind of influenza virus. The H5N1 virus subtype was found in Hong Kong in 1997 . It caused a massive poultry outbreak, killing about 1.5 million birds. The virus also infected and killed 18 people, making it the first case of a bird flu virus spreading from birds to humans.  Contact with infected surfaces can potentially transmit the infection. The avian flu virus may live for a brief time in food, but it becomes inactive at high temperatures. The virus can be killed by cooking food to an internal temperature of 70 degrees Celsius or higher.