A source generates three symbols with probabilities $0.25,0.25,0.50$ at a rate of $3000$ symbols per second. Assuming independent generation of symbols, the most efficient source encoder would have average bit rate as
- $6000 \; \mathrm{bits} / \mathrm{sec}$
- $4500 \; \mathrm{bits} / \mathrm{sec}$
- $3000 \; \mathrm{bits} / \mathrm{sec}$
- $1500 \; \mathrm{bits} / \mathrm{sec}$