After a Dry Spring, Rufous-Winged Sparrows in the Sonoran Desert

Multiple Choice

After a dry spring, rufous-winged sparrows in the Sonoran Desert wait for summer rainfall to stimulate the onset of reproduction. Sparrows likely use rainfall as an environmental cue because

A) rainfall is a predictable cue that ensures that they are primed for reproduction at the same time every year.
B) they live near the equator and the small changes in photoperiod are too difficult to use as a cue for reproduction.
C) the onset of the monsoon in the summer determines when sparrows migrate north for the breeding season.
D) they live in an arid, unpredictable environment where rainfall provides a more informative cue for resource availability and reproductive timing.