In Ecclesiastes, what recurring phrase marks Qohelet's skepticism about human endeavor, and what is the recommended response?

• A. Time is fleeting; the recommended response is to pursue wealth
• B. There is wisdom for every season; the recommended response is to plan carefully
• C. Vanity of vanities (hevel); the recommended response is to fear God and enjoy life as a gift within divine sovereignty
• D. All is vanity; the recommended response is to despair

Answer: (C)