4. choose the revision that corrects the run-on in the following sentence: people are living longer, the minimum age for social security benefits should be increased. a. people are living longer the minimum age for social security benefits should be increased. b. people are living longer, the minimum age for social security, benefits should be increased. c. people are living longer, so the minimum age for social security benefits should be increased. d. people are living longer so the minimum age for social security benefits should be increased