Hi, I was wondering if someone could please help me with the following question? I found it on the CASA prac exam questions - as far as I can work out I could not plan this flight as CMU unserviceable and the NDB at St George not falling within rated coverage?

ERC L4 refers.
You are flying at A100 by day from WALGETT, NSW (YWLG) (S3002 E14808) to CHARLEVILLE, QLD (YBCV), via W463.Additional chart information:
BEETI - SGE ..... track 080M, distance 80 nm
BEETI - CMU ..... track 261M, distance 78 nm
If CMU VOR is NOT serviceable during the period of your flight, which of the following pair of neighbouring beacons will permit you to fix your position at BEETI?