A、Fire. B、Mobile phone signals. C、Body bomb. D、Light. B

Another bomb has gone off in southern Thailand, the fourth in 24 hours. The latest blast that is reported to have injured four soldiers was in Yala province.
Even while senior government officials held an emergency meeting to discuss three bombs overnight, the fourth was detonated. The blast in Yala on Monday marks a return to form for violence in the southernmost provinces, where soldiers, police and local officials have been targeted by almost daily shootings and small explosions. But the attacks overnight represent a different kind of threat to Thailand’s national security.
The three explosions on Sunday killed two people and injured as many as 60. All of the blasts are thought to have been trigged by mobile phone signals in the first major attacks outside the southernmost provinces in the large cities of Hat Yai and Songkhla.
5.  What were the senior government officials doing when the last bomb went off?
6.  Who were targeted by daily shootings and small explosions in the southernmost provinces?
7.  What were the blasts triggered by?