Securities bought back must be extinguished and physically destroyed within how many days of completion of buy-back?

1. Step 1: Sec 68(6) requires extinguishment and physical destruction within 7 days of last date of completion. 2. Step 2: This ensures the bought-back securities cannot re-enter circulation. 3. Step 3: Hence (A). _Source: ICAI BoS CA Inter Paper 1, Ch 12 "Buy-Back of Securities"_