For a given bandwidth signal, more channel space is available for signals in the range ofa.LFb.VHFc.MFd.HF

The answer is b. VHF.

VHF (Very High Frequency) has a frequency range of 30 to 300 MHz, which is higher than LF (Low Frequency), MF (Medium Frequency), and HF (High Frequency). This means it has more bandwidth available for channel space.

Here's a step-by-step explanation:

1. LF (Low Frequency) ranges from 30 to 300 kHz.
2. MF (Medium Frequency) ranges from 300 kHz to 3 MHz.
3. HF (High Frequency) ranges from 3 to 30 MHz.
4. VHF (Very High Frequency) ranges from 30 to 300 MHz.

As you can see, VHF has a wider frequency range, which means it has more channel space available for signals.