Answer:
C. 3.2km
Explanation:
Seeing as the swimmer travels 10.8 km in an hour, and they are asking you to find how far they have traveled after 0.3 hours, multiply 10.8 km/h by 0.3 h. The h's will cancel and you are left with 3.24km, which can be rounded to 3.2km. Hope this helps! :)