Which of the following statements uses exact numbers? (a) 1 ft = 12 in. (b) 1 cal = 4.184 J (c) The height of Mt. Everest is 29,035 ft. (d) The world record for the 1-mile run, set by Morocco's Hicham el Guerrouj in July 1999, is 3 minutes, 43.13 seconds