Given data:
* The total distance traveled by the sprinter is d = 400 m.
* The total time taken in the given case is t = 52 seconds.
Solution:
The speed in the given case is,
![s=\frac{\text{total distance traveled }}{\text{total time taken}}](https://img.qammunity.org/2023/formulas/physics/college/ru98yomj2ehwabrgzd8j2a8f3q17inu7fo.png)
Substituting the known values,
![\begin{gathered} s=(400)/(52) \\ s=7.69\text{ m/s} \\ s\approx7.7\text{ m/s} \end{gathered}](https://img.qammunity.org/2023/formulas/physics/college/qtl26imkvo0v80gf7g9cxa2j74r9ztqh5p.png)
Thus, the speed of the sprinter is 7.7 m/s.
Hence, option B is the correct answer.