The correct answer is (a) VHF and UHF
The best explanation: Log periodic antenna uses around 30MHz to 3GHz frequency range.
MF – Medium Frequency – 300-3000 KHz
HF – High Frequency – 3-30 MHz
VHF – Very high frequency – 30-300 MHz
UHF – Ultra high frequency – 300MHz to 3GHz
So it uses VHF and UHF.