Complete the following sentence: "(...) When used for scientific research purposes, it is named scientific observation and has the purpose of enabl...

Complete the following sentence: "(...) When used for scientific research purposes, it is named scientific observation and has the purpose of enabling the ____________________ of the ______________ to be carried out."


a. Achievement of the objective; Investigation.
b. Research; Observation.
c. Performance of activities; Methodology.
d. Methodology; Research.