Indicate the statement that describes respiratory function in a highly trained athlete at maximal exercise.

a. Unchanged minute ventilation; increased respiratory rate; decreased vital capacity
b. Increased residual volume, respiratory rate; decreased alveolar ventilation
c. Increased tidal volume, unchanged minute ventilation and alveolar ventilation
d. Increased minute ventilation and alveolar ventilation, unchanged tidal volume
e. Increased tidal volume, minute ventilation and alveolar ventilation