Which of the following represents a conversion factor?

A conversion factor is a numerical value that helps convert a quantity from one unit of measurement to another while keeping the same quantity represented. In this case, the statement "1 mile = 1.61 km" serves as a conversion factor, as it defines the relationship between miles and kilometers. This allows for the conversion of distance measurements from miles to kilometers or vice versa by using this specific multiplier.

In contrast, the other options present potential conversions but may not reflect commonly used standard measures. The relationships given in B, C, and D might not accurately represent widely accepted conversion factors, especially when considering different contexts of measurement. It's essential to rely on standardized values, which is why option A is recognized as the valid conversion factor in this scenario.