Final answer:
Option C.
To calculate the average relative humidity in the afternoon in New Orleans, subtract the decrease of 17% from the morning's 83%, resulting in 66%. Thus, option c (66%) is the correct answer.
Step-by-step explanation:
The question asks us to calculate the average relative humidity in the afternoon in New Orleans.
We are told that the humidity in the morning averages 83% and decreases by 17% in the afternoon.
To find the afternoon humidity, we subtract 17% from the morning humidity of 83%, which equals 66%.
Relative humidity is defined as the ratio of the current absolute humidity to the highest possible absolute humidity, which depends on the current air temperature.
In this case, since we are provided with a percentage decrease rather than dealing with changes in temperature or absolute humidity, the calculation is straightforward and does not require additional weather knowledge.
Therefore, the correct option for the average relative humidity in the afternoon in New Orleans is c. 66%.