Using armored vehicles to detonate buried land mines entails an unavoidable risk of injury or fatality, but disarming and removing land mines manually currently entails an even greater such risk to those who remove land mines per mine removed. Therefore, in order to reduce the risk of injury or fatality without decelerating the effort to remove buried land mines, we must increase the use of armored vehicles and disarm fewer land mines by hand.

Which of the following, if true, most seriously undermines the argument above?

【选项】Manual mine disarmers can be quickly trained in methods that significantly decrease their risk of injury or fatality.