Which of the following statements with regard to Black Boxes used in modern aircrafts is/are correct? 1. They carry a beacon emitting red light pulses to facilitate underwater detection. 2. They record both the cockpit voice and flight data. 3. Their memory units are made using either stainless steel or titanium. Select the answer using the code given below:

Aircraft 'black boxes' actually consist of two units — the Cockpit Voice Recorder (CVR) and the Flight Data Recorder (FDR) — so statement 2 is correct. Their crash-survivable memory units are encased in protective shells made of stainless steel or titanium to withstand impact, fire, and deep-sea pressure, so statement 3 is correct. However, black boxes are equipped with an Underwater Locator Beacon (ULB) that emits ULTRASONIC PINGS (acoustic signals, typically at 37.5 kHz), NOT red light pulses — light cannot travel far underwater, which is why acoustic pingers are used. Statement 1 is incorrect. Hence statements 2 and 3 only are correct.