A garrison of 2000 men has provisions for 54 days. At the end of 15 days, a reinforcement arrives, and it is now found that the provisions will last only for 30 days more. What is the reinforcement?  Choose the correct choice from the following answers:
A) 1800 men	B) 3900 men	C) 600 men	D) 3800 men	E) 900 men

Rationale: "2000 - - - - 54 2000 - - - - 39 x - - - - - 20 x * 30 = 2000 * 39 x = 2600 2000 - - - - - - - 600 answer : c"
Answer: C