This question tells us that regions of natural beauty often have a lot of people move in and then businesses relocate to satisfy these new populations. The conclusion says that environmental protection programs would be beneficial to these regions, even if they hurt older local industries.
We are looking for a necessary premise that this argument requires.
E is absolutely necessary because if we were to negate it, we would have the following:
A factor harmful to some older local industries in a region need discourage other businesses from relocating to that region. If the government-mandated protection plan would cause mishap to both older local industries and new businesses, then the plan would then be useless.
I hope this helps. Please let me know if you have any other questions or would like me to elaborate further.