c. our lives go by quickly, so take time to enjoy each moment.
"History has taught our community that effective solutions occur only after long thought."
In order to eliminate redundancy in this sentence, we need to eliminate the word "past" at the beginning of the sentence. This is because the word is describing "history," but we already know that history refers to the past, which means we do not need this description. Redundancy refers to the use of words that provide information that is unimportant or obsolete because it was already provided in some other way.