GPS Satellites Go Around the Earth in Orbits That Have $26,600 \mathrm{~km}$

GPS satellites go around the earth in orbits that have a common radius of $26,600 \mathrm{~km}$ and a period of $12 \mathrm{~h}$ . Roughly how much less time would an atomic clock on a GPS satellite register between two events separated by exactly 24 $\mathrm{h}$ than clocks in the reference frame of the earth (ignoring gravitational effects on the satellite's clock rate) ?

A) About $10 \mathrm{~ms}$
B) About $1 \mathrm{~ms}$
C) About $100 \mu \mathrm{s}$
D) About 10 us
E) About 1 rs
F) About 10 ns