-  The words in each pairs are antonyms of each other

Expend and replenish are antonyms, meaning that they are opposite in meaning. Expend means to use up or consume resources, while replenish means to restore or fill again.

Let's examine the other options to determine which one has a similar relationship to expend:

A. Exhort: Encourage

Exhort and encourage are not antonyms, and they do not have a similar relationship to expend and replenish. Exhort means to urge or advise strongly, while encourage means to give support or confidence.

B. Foment: Rebellion

Foment and rebellion are not antonyms, and they do not have a similar relationship to expend and replenish. Foment means to incite or stir up, while rebellion means an act of resistance or defiance.

C. Defect: Rejoin

Defect and rejoin are antonyms, just like expend and replenish. Defect means to abandon or leave, while rejoin means to come back or reunite. This relationship mirrors the relationship between expend and replenish.

D. Encroachment: Occupy

Encroachment and occupy are not antonyms, and they do not have a similar relationship to expend and replenish. Encroachment means to intrude or trespass, while occupy means to inhabit or control.

Therefore, option C, Defect: Rejoin, is the correct answer.

In summary:

• Expend and replenish are antonyms, meaning that they are opposite in meaning.
• Option C, Defect: Rejoin, is the correct answer because it also has an antonym relationship.
• Defect means to abandon or leave, while rejoin means to come back or reunite.