Correct Answer - Option 3 : 4.33
The overall noise figure of cascade devices is \({F_n} = {F_1} + \frac{{{F_2} - 1}}{{{G_1}}} + \frac{{{F_3} - 1}}{{{G_1}{G_2}}} + \ldots + \frac{{{F_n} - 1}}{{{G_1}{G_2} \ldots {G_n}}}\;\)
We have,
gain = 10 dB = 10 and noise figure F = 6 dB = 100.6 = 3.98
Thus, overall noise figure:
\(\rm 3.98+\frac{3.98-1}{10} + \frac{3.98-1}{100} \)
= 4.32