The correct answer is option 2, Google. The Central Water Commission has recently formed a collaborative agreement with Google for flood forecasting. This partnership allows the Central Water Commission to leverage Google`s technology and expertise in data analysis and machine learning to improve their flood forecasting capabilities.

Option 1, Skymet, is not the correct answer. Skymet is a private weather forecasting company in India. While they may provide valuable weather information, they do not have a collaborative agreement with the Central Water Commission for flood forecasting.

Option 3, MetService, is also not the correct answer. MetService is a New Zealand-based meteorological service provider. They are not involved in the collaboration with the Central Water Commission.

Similarly, option 4, AccuWeather, is not the correct answer. AccuWeather is a private company that offers weather forecasting services globally. However, they do not have a collaborative agreement with the Central Water Commission for flood forecasting.

In conclusion, the Central Water Commission has entered into a collaborative agreement with Google for flood forecasting.