Gautami and Vashishta are the tributaries of:

Correct option is D

Correct Answer: (d) Godavari estuary
Explanation:
→ Gautami and Vashishta are distributaries/tributary channels of the Godavari river in its deltaic region.
→ They form part of the complex branching of the Godavari before it meets the Bay of Bengal.
Information Booster:
→ Godavari has an extensive delta with multiple channels used historically for irrigation and fisheries.
Additional Information (Other Options):
(a–c) Refer to different river systems not associated with Gautami/Vashishta.