A fertilizer company wants to determine the effectiveness of its new fertilizer on common garden plants. The company obtains a batch of seeds that are all of the same variety and produced at the same time by the same seed producer. They plant all the seeds in same-sized pots with similar soil and construct an environment ensuring that each plant is exposed to identical levels of water, light, and temperature. Half of the plants, chosen at random, are also treated with the new fertilizer. After several weeks, the plants treated with the fertilizer grow faster and larger, producing more fruit than the unfertilized plants. Upper Scenario involves which scientific method?
a. Prospective study
b. Controlled experiment
c. Retrospective study
d. Correlational method