C.
(i), (ii) and (iii) but not (iv)(c) Reason: Digital signals connot utilise decimal system which represents a continuous set of values.10 kHZ
10 MHz
1 GHz
1000 GHz
A.
10 kHZ
10 kHz cannot be radiated because the size of antenna is large. 1 GHz and 1000 GHz will penetrate.