Amountain climber starts a climb at an elevation of 453 feet above sea level. at his first rest stop he has climbed 162 feet, and by his second rest stop he has climbed another 207 feet. it's getting late in the day, so the climber starts his way down. if the climber descends 285 feet, how much does he need to ascend or descend to return to the original staring point?
a) ascend 84 feet
b) ascend 78 feet
c) descend 84 feet
d) descend 78 feet