Match the following: List I List II A. LED 1. Heavy Doping B. Avalanche Photodiode 2. Coherent Radiation C. Tunnel diode 3. Spontaneous Emission D. LASER 4. Current gain

• A-2, B-4, C-3
• A-2, B-3, C-1, D-4
• A-3, B-4, C-1, D-2
• A-2, B-1, C-4, D-3