Which excerpt from the text BEST illustrates the conclusion drawn in Part A?

What's the occasion? It'll be a chance to sit around and look at their phones together.

Smartphones are everywhere, and it seems as if they are here to stay. But is that a good thing?

Then there's the issue of our children and smartphones. Distraction and diminishment form only the tip of the iceberg-sized problem here.

"A man is rich in proportion to the number of things which he can afford to let alone," wrote Thoreau from an isolated cabin deep in the woods where a phone, smart or otherwise, had never rung.

The excerpt "Then there's the issue of our children and smartphones. Distraction and diminishment form only the tip of the iceberg-sized problem here." best illustrates the conclusion drawn in Part A.