Which one of the following is an artificial lake?

1. A

   Kodaikanal (Tamil Nadu)

   (a) Kodaikanal (Tamil Nadu). Kodai lake was created in 1863 by damming streams in the Palani Hills as an artificial reservoir for the hill station. Among the four, it is the man-made lake. This option is the official key.

2. B

   Kolleru (Andhra Pradesh)

   (b) Kolleru (Andhra Pradesh). Kolleru is a natural freshwater lake between the Godavari and Krishna deltas, a Ramsar wetland. It is not artificial. This option is not the key.

3. C

   Nainital (Uttarakhand)

   (c) Nainital (Uttarakhand). Naini Lake is a natural tectonic/depression lake of the Kumaon Himalaya. This option is not the key.

4. D

   Renuka (Himachal Pradesh)

   (d) Renuka (Himachal Pradesh). Renuka is a natural lake in Sirmaur, tied to the Renuka fair, not an excavated tank. This option is not the key.

Summary. Official key is (a) Kodaikanal. The Palani Hills lake at Kodaikanal is a 19th-century constructed reservoir. Kolleru, Nainital and Renuka are natural waterbodies—deltaic, tectonic and Himalayan respectively. Only (a) therefore answers “artificial lake”. That is the stored letter.