Not necessary, because the author believes the protection would help preserve a regions’ natural beauty. (A) states that the natural beauty would attract residents, but only until the protection is imposed. This undermines the author’s reasoning.

Not necessary, because the author acknowledges that the protection may harm some older local industries. The author believes that the benefit to the economy from new business attracted to the region would outweigh the harm to older local industries.

Not necessary, because there can be other, more important ways that the protection helps the economy. As long as encouraging people to move into the region is one way the protection helps the economy, the author’s reasoning still works.

Not necessary, because the author didn’t conclude that we must use government-imposed protection to help the economy. The author merely said that such protection “can” help the economy; this allows for other methods to help the economy, such as voluntary protection measures.

Necessary, because if it were not true — if a factor harmful to some older local industries (the gov. protection) NEEDS to discourage other businesses from relocating to that region — then we cannot assume that new businesses will relocate to the region. Although they’d be encouraged by a growing population, they’d be discouraged by the government protection.