In a D flip-flop, the set and reset functions can be either synchronous or asynchronous. Synchronous means that the reset is synchronized with the clock, activating only on a specific clock edge, while asynchronous allows the reset to occur independently of the clock state. The discussion highlights confusion about whether the set and reset should operate simultaneously or independently. Clarification is provided that asynchronous resets can override the clock, while synchronous resets depend on the clock signal. Understanding these distinctions is crucial for proper implementation in digital circuits.