Step 1: Recall liquidity concept.
Liquidity = how quickly an asset can be converted into cash without loss of value.
- Highest liquidity → Currency and demand deposits (most liquid).
- Then savings deposits.
- Then time deposits.
- Least liquid → broader aggregates with post office deposits.
Step 2: Order the options.
- (C) Currency + Demand Deposit → Most liquid (M1).
- (A) Currency + Demand + Savings deposits (Post Office) → Next liquid.
- (D) Currency + Demand + Net time deposits (M2/M3).
- (B) Currency + Demand + Net time + Post Office deposits (broadest, least liquid).
Step 3: Correct sequence.
Thus, order is: (C), (A), (D), (B).
Final Answer:
\[
\boxed{(C), (A), (D), (B)}
\]