Step 1: Recall the rule:
The regulator wants a new issue to be nearly fully subscribed before allotment. This protects investors from a company that has not raised enough money for its plan.
Step 2: State the figure:
The SEBI guidelines of 2000 fix this floor at 90% of the issue. Below this, no allotment can be made, and money is refunded.
Step 3: Compare with the choices:
Since 90% is the floor, any smaller figure such as 60%, 70% or 80% cannot be the minimum. So the answer is the fourth option.
Final Answer:
Option (4).
\[ \boxed{90\% \text{ of the issued amount}} \]