A Patient Receives M Milligrams of a Certain Drug Every $\sum _ { \mathrm { k } = 1 } ^ { \infty } \mathrm { Mp } ^ { \mathrm { k } }$

A patient receives M milligrams of a certain drug every hour. Each hour the body eliminates a fraction p of the amount of drug in the body. After an extended period of time, which of the following series approximates the amount of drugs present in the patient's body immediately before receiving an hourly dose?

A) $\sum _ { \mathrm { k } = 1 } ^ { \infty } \mathrm { Mp } ^ { \mathrm { k } }$
B) $\sum _ { \mathrm { k } = 0 } ^ { \infty } \mathrm { Mp } ^ { \mathrm { k } }$
C) $\sum _ { \mathrm { k } = 0 } ^ { \infty } \mathrm { M } ( 1 - \mathrm { p } ) ^ { \mathrm { k } }$
D) $\sum _ { \mathrm { k } = 1 } ^ { \infty } \mathrm { Mp } ^ { - \mathrm { k } }$
E) $\sum _ { \mathrm { k } = 1 } ^ { \infty } \mathrm { M } ( 1 - \mathrm { p } ) ^ { \mathrm { k } }$