# Frequencies in the UHF range are normally propagated by means of

$\begin{array}{1 1}(a)\;\text{Ground waves}\\(b)\; \text{Sky waves}\\(c)\;\text{Surface waves}\\(d)\;\text{Space waves}\end{array}$

Ultra high frequency band (UHF) from 300Hz to 3000MHz are normally propagated by space waves.
Hence (d) is the correct option.