Concept:
The traditional sequence of Bharata Natyam performance is known as the Margam. It was systematized to present dance items in a progressive order from pure rhythm and movement to expressive and elaborate performance.
Step 1: Understand the Bharata Natyam repertoire sequence.
The important items in the Bharata Natyam Margam generally follow this order:
\[
\text{Alarippu} \rightarrow \text{Jatiswaram} \rightarrow \text{Shabdam} \rightarrow \text{Varnam}
\]
Each item gradually increases in complexity and expressive depth.
Step 2: Understand the role of each item.
• Alarippu -- Opening invocatory item focusing on rhythm and body movement.
• Jatiswaram -- Combines dance patterns with musical swaras.
• Shabdam -- Introduces expressive storytelling and abhinaya.
• Varnam -- Central and most elaborate item combining nritta and nritya.
Step 3: Identify the correct sequence using the letters.
Using the given labels:
\[
A = \text{Alarippu}
\]
\[
C = \text{Jatiswaram}
\]
\[
B = \text{Shabdam}
\]
\[
D = \text{Varnam}
\]
Thus, the correct sequence is:
\[
A,\ C,\ B,\ D
\]
Step 4: Compare with the given options.
Among the given choices:
\[
(A)\ B,C,D,A
\]
\[
(B)\ A,C,B,D
\]
\[
(C)\ C,B,A,D
\]
\[
(D)\ A,B,C,D
\]
the correct answer is:
\[
\boxed{A,C,B,D}
\]
Hence:
\[
\boxed{\mathrm{(B)}}
\]