Identify the option that contains the correct sequence of Indian states in terms of decreasing average annual rainfall.

To identify the correct sequence of Indian states in terms of decreasing average annual rainfall, we can analyze the general climatic and geographical features of each state:

1. Assam: Located in Northeastern India, Assam receives very heavy rainfall due to the Southwest monsoon and its hilly topography. The average annual rainfall in Assam is typically between 250 cm and 300 cm, making it one of the wettest regions in the country.
2. Bihar: Situated in the eastern plains of India, Bihar receives moderate to high rainfall, primarily from the Southwest monsoon. The average annual rainfall here ranges from about 100 cm to 150 cm.
3. Rajasthan: Located in northwestern India, Rajasthan is predominantly an arid to semi-arid region containing the Thar Desert. It receives very low rainfall, with the average annual rainfall ranging from less than 15 cm in the extreme west to about 50 cm to 60 cm in the eastern parts.

Comparing the average annual rainfall of these three states:
Assam (approx. 250-300 cm) > Bihar (approx. 100-150 cm) > Rajasthan (approx. 15-60 cm)

Therefore, the correct sequence in terms of decreasing average annual rainfall is Assam > Bihar > Rajasthan.