Laser Beam is produced due to _____

• A. spontaneous emission
• B. stimulated emission followed by spontaneous emission
• C. spontaneous emission followed by Spontaneous absorption
• D. spontaneous absorption leading to ‚Äö√Ñ√∂‚àö√ë‚àö‚à´population inversion‚Äö√Ñ√∂‚àö√ë‚àöœÄ and followed by stimulated emission