Step 1: Understanding Functions of a Stock Exchange
A stock exchange facilitates trading by providing liquidity, ensuring safety, and promoting investments.
Step 2: Evaluating the Given Statements
- (A) Liquidity and marketability of securities are key functions of stock exchanges.
- (B) Stock exchanges encourage public participation in equity investment.
- (C) Transactions are regulated for safety.
- (D) Stock exchanges cannot entirely eliminate speculation, as it is a part of market operations.
Conclusion: The correct answer is (mathbf{(D)}), as speculation exists in every financial market.