Gregory wanted to know what type of food spiders prefer to eat, so he performed two different investigations.

In one investigation, he observed a spider in his backyard every day for thirty days. He wrote down what the spider ate each day.

In another investigation, he placed the same type of spider in an aquarium that recreated a portion of his backyard environment. Each day, for thirty days, Gregory placed four different items in the aquarium—a leaf, a cricket, a fly, and a beetle. Then, he wrote down which item the spider chose to eat first.

Which investigation produced the most reliable results?

A. Neither investigation would produce useful data.
B. The first investigation would produce more reliable results because it only required daily observation.
C. Both investigations have benefits and limitations and should be examined together to get the most reliable result.
D. The second investigation would produce more reliable results because Gregory was able to control the conditions of the experiment.