Based on the thesaurus entry and how the word is used in the paragraph, which word is the closest meaning for conservation and why is that meaning the best choice?

john muir visited yosemite valley in california as a young man. he found the valley beautiful. but muir saw the meadows being ruined by grazing sheep. many of the giant trees were being cut down. muir wrote about the valley and its beauty. he pushed for conservation of the valley. in 1890, yosemite valley became a national park for all to enjoy.

read the thesaurus entry.

conservation, n. control, maintenance, protection, preservation

a.
control

it tells how no one was in charge of what was going on in yosemite valley.

b.
maintenance

it explains how the meadows were being taking care of by the sheep.

c.
protection

it tells how john muir wanted to keep the giant trees from being cut down.

d.
preservation

it tells how the beauty of yosemite valley has been saved for the future.
hurry