This question is asking how important safety and reducing risk to life is to you. Some options may provide safety to particular flood levels but may cause significant risk to life if these levels are exceeded. Other options provide mechanisms to reduce risk to life and improved safety no matter what level the flood waters reach.
Local flood warning systems and flood forecasting for example provides safety to the community as these systems give community members in advance the opportunity to know what is likely to occur, prepare for flooding, and move to a safe area or evacuate. They also provide a heads-up to emergency service personal to prepare for and respond to flood impacts.