Which of the following everyday occurrences results from a spontaneous process?

A spontaneous process is a physical or chemical change that occurs by itself. The change requires no input of work or energy in any form.

Which of the following everyday occurrences results from a spontaneous process?
A . water boiling
B . iron rusting in moist air
C . hydrocarbon emissions from gasoline combustion
D . water freezing
E . snow melting

Answer: B