Which of the Following Persons Is Most Likely to Maintain

Which of the following persons is most likely to maintain good intellectual functioning into old age?

A) Sarah, of average intelligence, who does the crossword puzzle every day and takes a brisk one-hour walk each morning
B) Jim, who has a high IQ and reads regularly, but rarely exercises
C) Paul, who has a high IQ, runs three miles each day, and plays handball regularly, but doesn't read even the daily paper
D) We do not have enough information to make a prediction.