If F1 and F2 are the lower and upper cutoff frequencies of a band pass signal, then what is the condition to be satisfied to call such a band pass signal as narrow band signal?

• A. (F1-F2)>\(\frac{F_1+F_2}{2}\)(factor of 3 or less)
• B. (F1-F2)⋙\(\frac{F_1+F_2}{2}\)(factor of 10 or more)
• C. (F1-F2)<\(\frac{F_1+F_2}{2}\)(factor of 3 or less)
• D. (F1-F2)⋘\(\frac{F_1+F_2}{2}\)(factor of 10 or more)