An astronomer measures a galaxy’s distance from the Earth as $2.5 \times 10^{21}\ \text{km}$ in order to determine the value of the Hubble constant. She also finds that the galaxy is receding from the Earth at a speed of $5.2 \times 10^{3}\ \text{km s}^{-1}$. Using these data, what is the value of the Hubble constant?
- A$7.7 \times 10^{-26}\ \text{s}^{-1}$
- B$2.1 \times 10^{-18}\ \text{s}^{-1}$
- C$4.8 \times 10^{17}\ \text{s}^{-1}$
- D$1.3 \times 10^{25}\ \text{s}^{-1}$