Correct Answer:

A: a work of grammar

Explanation of Options:

Option A is correct: a work of grammar  
 • The Tolkappiyam is an ancient Tamil text that is considered the earliest work on Tamil grammar and linguistics.
 • It is a comprehensive treatise that covers phonetics, morphology, syntax, and semantics of the Tamil language.
 • The text is traditionally attributed to the scholar Tolkappiyar and is divided into three sections: Ezhuttadikaram (phonology), Solladikaram (morphology and syntax), and Poruladikaram (semantics and rhetoric).
 • It is a foundational work in Tamil literature and has been influential in the study and preservation of the Tamil language.

Option B is incorrect: a Tamil poem in praise of Rajendra Chola  
 • The Tolkappiyam is not a poem, nor is it specifically related to any Chola king, including Rajendra Chola.
 • Rajendra Chola was a prominent Chola emperor known for his military conquests and administration, but the Tolkappiyam predates his reign.
 • The text is focused on linguistic and grammatical aspects rather than historical or royal praise.

Option C is incorrect: an ancient didactic work in Tamil  
 • While the Tolkappiyam is ancient and written in Tamil, it is not primarily a didactic work in the sense of providing moral or ethical teachings.
 • Its primary focus is on the structure and rules of the Tamil language rather than imparting moral lessons or instructions.

Option D is incorrect: a drama composed by a Chera King  
 • The Tolkappiyam is not a drama, nor is it associated with any Chera king.
 • It is a scholarly work on grammar and does not belong to the genre of drama or theatrical compositions.
 • The Chera dynasty was one of the ancient Tamil dynasties, but there is no historical evidence linking the Tolkappiyam to any Chera ruler.