Step 1: Understanding the Concept:
Book building is a mechanism where, during the period for which the IPO is open, bids are collected from investors at various prices.
Step 2: Detailed Explanation:
The NSE electronic system provides transparency, speed, and cost-efficiency.
(A), (B), and (C) are genuine benefits of the automated book-building process.
(D) is incorrect because the stock market and IPO bidding follow specific exchange hours (e.g., 10 AM to 5 PM) and are not open 24/7.
Step 3: Final Answer:
(D) The IPO market 24/7.