5. On 1 November 2018, you bought on margin 1000 shares of Singapore Airlines at $7.2 per share. You put $5400 to your margin account according to the Initial Margin Requirement. The annual interest rate is 10%. On 1 November 2019, the margin is triggered. Assume the Maintenance Margin Requirement is 50%, how much money you need to top up? A) B) C) D) $990 $1000 $1100 $490