Explanation: An AND gate is the correct choice because its fundamental operation dictates that its output will be active high (logic '1') *only if* all of its inputs are simultaneously active high. This behavior is precisely what the question describes. Conversely: * A **NAND** gate provides an active *low* output when both inputs are active high (it's the inverse of an AND gate). * A **NOR** gate provides an active *low* output if *any* of its inputs, including both, are active high. * An **XOR** (exclusive OR) gate provides an active *low* output when both inputs are the *same* (either both high or both low). Understanding these basic logic gate functions is crucial for designing and troubleshooting digital circuits common in amateur radio equipment, such as frequency counters, control systems, and data encoders/decoders.