<p>Tourists to Iceland, (drawn to the edge of the raging river that will soon fill up to become a lake because of the coming dam, will change) the river's valley significantly.</p>
<p>B. drawn to the edge of the raging river that will soon fill up to become a lake because of the coming dam, will see the dam change
D. who are drawn to the edge of the raging river that will soon fill up to become a lake because of the coming dam, will see the dam change, see changes in</p>