A multipurpose reservoir is the one which is A. designed for one purpose but serves more than one purpose B. planned and constructed to serve various purposes C. both (A) and (B) D. none of the above

The correct answer is C. both (A) and (B).

A multipurpose reservoir is a reservoir that is planned and constructed to serve various purposes, such as water supply, irrigation, flood control, and hydroelectric power generation.

Option A is incorrect because a multipurpose reservoir is not designed for one purpose but serves more than one purpose. It is planned and constructed to serve various purposes.

Option B is incorrect because a multipurpose reservoir is not just planned and constructed to serve various purposes. It is also designed for that purpose.

Option D is incorrect because a multipurpose reservoir is both designed and constructed to serve various purposes.