See Seeds, Fig. 6-2 where he orders the spectrum left to the right in order of increasing wavelength.
Energy of photon is directly proportional to frequency, but inversely proportional to wavelength.
I prefer to think of resolving power as a quantity for which 'bigger is better'. In light of this potential confusion between my interpretation and Seeds', I accept a or b as correct answers. The answer to A6. is not affected by this confusion A6. L red . L red .