Final answer:
The word 'wane' matches the phrase 'on the decrease,' indicating a reduction over time in size, amount, or strength.
Step-by-step explanation:
The correct match to the word "wane" from the given options would be a) on the decrease. The word "wane" means to decrease in size, extent, or degree. It is often used to describe a phase of the moon where it appears to become gradually thinner or less full, but it can also be used more broadly to describe anything that is diminishing or reducing in strength or intensity.
Therefore, 'on the decrease' is analogous to 'wane,' as both indicate a reduction in size, amount, or strength over time. Lastly, 'devastation,' 'exude,' and 'prosper' do not fit the meaning of 'wane' since they refer respectively to great destruction, to discharge or emit a liquid or gas slowly, and to be successful or thrive.