A Clock Pendulum Made of Aluminum,which Has a Coefficient of Linear

Multiple Choice

A clock pendulum made of aluminum,which has a coefficient of linear expansion of 24 $\times$ 10^-6/K,has a period of exactly 1 s at 20ºC.Before a homeowner leaves town for one week,he turns the thermostat down to 10ºC.When he returns,the clock is

A) fast by about 73 s.
B) fast by about 7.6 min.
C) exactly on time.
D) slow by about 7.6 min.
E) slow by about 73 s.