Which sentence summarizes, rather than evaluates?

a: smith presents interesting evidence for those who believe that we should be trying to combat climate change now rather than later.
b: it is far too early to know whether smith's predictions about climate change will be borne out.
c: when people complain about "suffering from global warming" on a hot summer day, smith says, they have little idea what they are saying.
d: perhaps another way to think about smith's work is that it is a first glimpse into a field we are only recently beginning to understand.