Answer:
D. 8
Step-by-step explanation:
If we divide the number of riders of a day by the number of riders of the day before, we get:
![\begin{gathered} (56)/(7)=8 \\ (448)/(56)=8 \\ (3,584)/(446)=8 \\ (26,672)/(3,584)=8 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/90efr7rnolxtlqe4ei16a257acruzve5tb.png)
Therefore, the number of riders changes each day by a factor of 8 because each day the number of riders is 8 times the number of riders of the day before.