Step 1: Understanding the Concept of Rasa.
The theory of `rasa' explains how aesthetic pleasure is experienced by an audience through emotions depicted in art and drama.
Step 2: Source of the Theory.
The concept was systematically formulated by Bharata Muni in the Natya Shastra, an ancient Sanskrit treatise on dramaturgy.
Step 3: Analysis of Options.
Abhigyana Shakuntalam is a play, while Manu Smriti and Charaka Samhita are legal and medical texts respectively.
Step 4: Conclusion.
Thus, the correct answer is option (A).