The Spill of Cyanide into the Tisza and Danube Rivers

The spill of cyanide into the Tisza and Danube Rivers in 2000 could have been prevented if

A) the computer systems monitoring the cyanide volume had not crashed
B) fewer people had withdrawn water from the rivers so the overall flow rate was lower
C) an earthquake warning system had been in place to warn dam managers of the impending quake that broke the dam
D) the mining company had installed a stronger containment dam and a backup settling pond to prevent leakage
E) a newer, more technologically sound settling pond had been in place