Which phrase is most likely to start a description of a scientific theory? a. "what i have found through my online research is . ." b. "after much thought, i believe that the best explanation is . ." c. "based on the observations made and experiments performed over the last fifty years . ." d. "if sunlight shines on the right side of a plant, then the plant will grow toward the right because . ."

The correct answer will be option-C.

Explanation:

A scientific theory is a well explained proved idea or opinion about any aspect related to the natural world.

The scientific theories are based on the proved facts and not guesses which are proved through the experiments and observations and can lead to the generation of correct scientific answers.

Since Option-C states about the "experiment and observation" recorded in the last 50 years are the correct answer.