The correct answer is: A. A 15o F air temperature and 0 MPH winds.
Wind chill is a measure of how cold it feels when the wind is blowing. It is calculated using the following formula:
Wind chill = 35.74 + 0.6215T – 35.75(V^0.16) + 0.4275T(V^0.16)
where T is the air temperature in degrees Fahrenheit and V is the wind speed in miles per hour.
In this case, the air temperature is 45 degrees Fahrenheit and the wind speed is 30 miles per hour. Plugging these values into the formula, we get a wind chill temperature of 15 degrees Fahrenheit. This means that it feels like it is 15 degrees Fahrenheit outside, even though the actual air temperature is 45 degrees Fahrenheit.
The other options are incorrect because they do not take into account the effect of the wind. A 30-degree Fahrenheit air temperature with no wind is not the same as a 15-degree Fahrenheit air temperature with 30-mile-per-hour winds. The wind chill temperature is a more accurate measure of how cold it feels outside.