Which is the safest area for towing a skier? near the shoreline where others can watch near other skiers or swimmers in the water in the middle of the lake away from other boaters in the heavy-traffic area of the waterway?

The answer would be in the middle of the lake away from other skiers or swimmers in the water. 

Given the choices that would be the best answer because it is the safest. When towing a skier, you need to be at a safe distance from hazards like the shoreline, swimmers, boats, and skiers. It is advisable that you distance yourselves at least twice the length of the rope you will use for towing.