26.2 miles converts to 42.16 kilometers.

To convert miles to kilometers, the conversion factor of 1 mile equals 1.60934 kilometers is used. Multiplying 26.2 miles by this factor provides the correct distance in kilometers, which rounds to 42.16.

A) 421.65 kilometers
This option incorrectly multiplies the mile distance too low, resulting in a value that misrepresents the conversion. The correct calculation yields a value significantly higher than 421.65 kilometers.

B) 4216.47 kilometers
This answer is an overestimation, stemming from a miscalculation that likely involved incorrect multiplication or unit conversion. The distance should be much lower than this inflated figure when properly converting 26.2 miles.

C) 42164.71 kilometers
This choice is drastically incorrect, suggesting a misunderstanding of the conversion scale. The figure is excessively high and does not reflect a plausible distance for a marathon, indicating a complete miscalculation.

D) 42.16 kilometers
This is the correct conversion of 26.2 miles to kilometers, as it accurately applies the conversion factor and rounds the result to the nearest hundredths. The calculation (26.2 miles * 1.60934 km/mile) equals approximately 42.164, which rounds to 42.16 kilometers.

Conclusion
Converting miles to kilometers requires the application of the conversion factor of 1 mile to 1.60934 kilometers. For a marathon distance of 26.2 miles, the accurate conversion yields 42.16 kilometers. The other options reflect various degrees of miscalculation, underscoring the importance of precise mathematical conversion in unit changes.