If the prescribed dose of morphine is 0.10 mg of drug per kg of patient’s weight for acute pain, what volume of a 4 g/L morphine solution should be given to a 200 pound adult patient? (2.2 lb = 1 kg).

1. 2.3 mL
2. 11mL
3. 37mL
4. 200 mL 

I know that the answer is 2.3 mL. However, can someone give me a clear step by step explanation of how to solve this problem. Thank you.