An Athlete in the Early Weeks of an Aerobic Training

An athlete in the early weeks of an aerobic training program develops a decreased hemoglobin concentration but does not report disproportionate fatigue. Which of the following statements is true of the athlete's decreased hemoglobin levels?

A) Decreased hemoglobin concentrations are never a cause for concern.
B) The athlete has an iron deficiency.
C) The athlete has a low blood volume.
D) Vitamin and mineral supplements are necessary to reverse this condition.