How do the designs of Experiments 1 and 2 differ in terms of sampling procedure?

A. In Experiment 1, the lake water was tested, while in Experiment 2 feeder stream water was tested.
B. In Experiment 2, lake water was tested, while runoff water was tested in Experiment 1.
C. In Experiment 1, only phosphate concentration was tested, while in Experiment 2, only nitrate concentration was tested.
D. In Experiment 2, chlorophyll level was tested in addition to phosphates and nitrates, while in Experiment 1, it was not.

Experiment 1
Scientists suspected that one source of nutrients was a feeder stream which intercepts run-off from farmland where pesticides and animal waste are found. Water samples were obtained over several days from that stream (Feeder A) as well as another feeder stream (Feeder B) not near the farm. Results are displayed in Table 1.

Experiment 2
The scientists also surmised that another possible source of harmful nutrients entering the lake was run-off from a golf course adjacent to the lake where fertilizers were applied.
Water samples were obtained from the lake at various distances (0 meters, 100 meters and 200 meters) from the golf course on four successive days, and the levels of chlorophyll, phosphates, and nitrates were measured. The results are depicted in Table 2.

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Day Day 1 Day 2 Day 3 Day 4 Day 1 Day 2 Day 3 Day 4 Phosphate concentration (mg/L) 20.7 13.2 35.6 42.3 Table 1. 10.4 11.5 7.9 10.2 Feeder A Feeder B Nitrate concentration (mg/L) 43.2 44.5 41.6 58.0 13.2 13.4 12.9 11.4