The Centre has reconstituted an (A)/advisory committee to chalk out a plan…

Concept: In error-spotting questions, each underlined part must be checked on its own for tense, idiom, and correct word form. Describing something as “of myth/legend” requires the adjective form — “mythical” or “mythic”; “mythics” is not a standard English word for this construction, even though English does allow some nouns to modify other nouns elsewhere (e.g., “sports car”).

Application: The word “mythics” is used here to describe “Sarasvati River” as legendary. But “mythics” is not the standard or correct word for that meaning. The idiomatic, correct word is the adjective “mythical” (or “mythic”), giving “…for studying the mythical Sarasvati River…”. This is the error in the sentence.

Cross-check: Substituting the adjective confirms the fix reads naturally and idiomatically — “…for studying the mythical Sarasvati River for the next two years…” — exactly the standard phrasing used to describe a river tied to legend.

Why the rest of the sentence is correct:

• “Reconstituted”: the correct past-participle form after “has”, matching the meaning “formed again” and the sentence’s present-perfect tense.

• “Chalk” (in “chalk out a plan”): “chalk out” is a standard idiomatic phrasal verb meaning “to draft/plan”, used correctly here.

• “Earlier”: correctly used as an adjective referring to the previously constituted panel, with the possessive “panel’s term” formed properly.

Corrected sentence: The Centre has reconstituted an advisory committee to chalk out a plan for studying the mythical Sarasvati River for the next two years, after the earlier panel’s term ended in 2019.