Bioavailability of an intravenous drug is always 100% by definition because:

• A. Bioavailability measures the amount of substance that reaches the bloodstream.
• B. Absolute bioavailability is 50%, for any drug taken intravenously
• C. Absolute bioavailability is a much more important measure than relative bioavailability
• D. Intravenous administration gets the drug into your bloodstream the fastest.