Final answer:
The speed of the swimmer in still water is 1.4 m/s, which is equal to 5.04 km/h.
Step-by-step explanation:
The speed of the swimmer in still water is 1.4 m/s. To convert this to km/h, we need to multiply by a conversion factor. 1 m/s is equal to 3.6 km/h, so the speed of the swimmer in km/h is 1.4 m/s x 3.6 km/h = 5.04 km/h. Therefore, the correct answer is option 1) 5.04 km/h.