The correct answer is option 4: Monsoon experiment.
MONEX stands for Monsoon Experiment, which is a scientific research project focused on studying and understanding the monsoon climate system. The experiment aims to gather data and observations related to the monsoon in order to improve the understanding and prediction of monsoon patterns and their impact on weather and climate.
Option 1 (Montreal experiment) is incorrect as it does not pertain to MONEX. The Montreal Experiment refers to a different research project or experiment conducted in Montreal.
Option 2 (Monetary experiment) is also incorrect as it does not relate to MONEX. A monetary experiment typically refers to studies and experiments related to monetary policy, banking systems, or economic theories, rather than the study of weather patterns.
Option 3 (Lunar experiment) is incorrect as MONEX does not relate to the moon or lunar studies. Lunar experiments typically refer to research conducted on or relating to the moon.
Therefore, the correct answer is option 4 (Monsoon experiment).