Which option most accurately states a central idea of ""Principles of Conservation""?

The options are not given but the answer is;

The Central idea is "Conservation means the greatest good to the greatest number for the longest time'

Explanation:

The Central idea in a sentence or speech is the main point the writter is making and wants the reader to infer to it or remember it most.

The Central idea is the main idea or main point of the write up or aticle . It usually the first sentence in a write-up and the writer give more details or information to support it.

From the question, the Central idea is conservation means the greatest good to the greatest number for the longest time

it will show up when more than one person gives an answer

the following key ideas correctly express the key sentence.

restate key idea: most people can learn to swim in ten short lessons.

restate key idea: the majority of water-accident victims require mouth-to-mouth breathing.

restate key idea: an empty, tightly closed gallon jug will support a tired swimmer.  

restate key idea: first aid is to prevent accidents as well as assist in rescue.

explanation: the key idea needs to have the same topic as the key sentence (drowning and safety).