Based on the description of the picture, the most likely conclusion is:
d. all of the above
Here's the reasoning for each option:
a. The temperature at night is cold. - In desert areas, like those indicated by sand dunes, temperatures can drop significantly at night. This is plausible.
b. This place gets very little rain each year. - El Azizia, Libya, is known to be a desert region, which typically experiences very little rainfall.
c. The temperature can rise to more than 100º F. - Given that El Azizia is in a desert climate, it is also likely that temperatures can soar above 100º F during the day.
Therefore, the most comprehensive conclusion considering the visual context is "all of the above."