A stockist wants to make some profit by selling sugar. He contemplates about various methods. Which of the following would maximise his profit?
- Sell sugar at $10\%$ profit.
- Use $900$ g of weight instead of $1$ kg.
- Mix $10\%$ impurities in sugar and selling sugar at cost price.
- Increase the price by $5\%$ and reduce weights by $5\%$.
- I or II
- II
- II, III and IV
- Profits are same