Mr. Larsen reports constipation. The attending physician prescribes docusate sodium syrup 100 mg PO BID. The concentration is 50 mg/ 5 mL. How many mL of docusate sodium syrup should you administer to Mr. Larsen?
a) 5 mL
b) 10 mL
c) 15 mL
d) 20 mL