Concept:
Tabla compositions are classified into two structural types based on how they are performed: expandable forms (Vistarshil, such as Kaydas or Peshkars, which allow the artist to improvise variations) and fixed forms (A-Vistarshil, such as Tukdas or Mukhdas, which are played exactly as written).
Step 1: Evaluate Assertion (A).
Assertion (A) states that a Tukda is an unexpandable composition (A-Vistarshil). A Tukda is a short, pre-composed piece that uses a fixed sequence of drum syllables and concludes with a structural Tihai. Since it must be performed exactly as written without improvising variations or Paltas, it is classified as unexpandable. This makes Assertion (A) true.
Step 2: Evaluate Reason (R).
Reason (R) states that a Tukda can be expanded. As established above, a Tukda has a fixed structural framework and does not permit spontaneous variation or thematic expansion during a performance. Since it cannot be expanded, Reason (R) is factually incorrect.