A grandfather clock measures time by counting the number of oscillations of a small-angle pendulum. You take a grandfather clock that gives the correct time at sea level (where g = 9.81m/s²) up a mountain and notice that after two days it is running five minutes behind. What is the value of the gravitational acceleration up that mountain?
a) 9.74m/s²
b) 9.78m/s²
c) 9.84m/s²
d) 9.81m/s²
e) There is not enough information to answer the question