China and Thailand are fighting fresh outbreaks of the highly contagious bird flu, which killed 24 people in Southeast Asia earlier this year. Authorities in both China and Thailand assured frightened residents the new outbreaks of the deadly H5N1 strain of the avian flu were under control and the threat of a mass epidemic is unlikely. There have been no cases of transmission to humans in either country so far.In China, officials say the virus was discovered on a farm approximately 300 kilometers west of Shanghai. Residents of the infected farm have been quarantined and all poultry within two kilometers have been killed.Officials say they will strengthen a quarantine of local poultry markets to further reduce the risk to people in the area. Julie Hall of the World Health Organization says Chinese authorities are acting to contain the virus. "They’ve been able to detect these birds are getting sick and they’ve put in place the correct measures and enhance surveillance," she says.China announced it wiped out the lethal strain of the bird flu four months ago and blamed this most recent outbreak on migratory birds.In Thailand lab tests confirmed outbreaks on two farms in towns near Bangkok. Thousands of chickens on those farms have been destroyed and officials insist there is no evidence the disease has spread. This is the first confirmed outbreak in Thailand since April. Thailand is the world’s fourth largest exporter of chickens and bans on its poultry exports have damaged the national economy.Previous outbreaks of the deadly flu in Asia this year led to the destruction of 100 million fowl and fueled concerns of massive human fatalities. Sixteen people died in Vietnam and another eight in Thailand.The deadly H5N1 strain of the avian flu was first discovered in humans in Hong Kong in 1997. The flu is transmitted from live poultry to humans but doctors say it cannot be spread in cooked food and the risk of infection remains slight. What's the most likely reason for the new outbreak in China, according to Chinese officials()

A. Surveillance failure.
B. Migratory birds.
C. Lack of regulations and rules.
D. Lack of money.