At a garments shop, Ramesh can buy 2 trousers and 4 shirts for an amount of Rs. 1,600 or he can buy 1 trouser and 6 shirts for exactly the same amount of Rs. 1,600. What will be his bill amount, if he buys only 12 shirts?

• A. Rs. 4,200
• B. Rs. 2,400
• C. Rs. 1,800
• D. Rs. 1,200