Why was letting sea water evaporate in the sun not efficient, or good, method for obtaining salt?

we need the answer choices to answer the question

if you're talking about (ww2) they went bankrupt and their currency was worth nothing

explanation:

the correct answer is: the sioux followed the order and remained on the reservation.

after many confrontations between native americans and white american, in 1868, a reservation for the lakota sioux tribe was established in dakota territory, in this reservation they were able to hunt ad to move freely. in 1874, many sioux followed the order, given by the federal government, of remaining on the reservation in which they were already living. the problem arose when, in 1874, gold was found in that area by lieutenant george armstrong custer's military troops, and lieutenant custer insisted that the sioux must give up their reservation land in the black hill of the dakotas.

the united states government opted for moving the sioux to a new reservation. siting bull, leader of the lakota sioux, protested the united states government's demands for the lands where the lieutenant custer's soldiers found the gold. but finally they left the reservation lands and went to a camp along the little bighorn river in 1876.    

i beleive a. is the only possible answer