✅ The relationship between VIRUS and ILLNESS is one of cause and effect; a virus is the cause that leads to illness as its effect.

In option A, EXERCISE is the cause that leads to FITNESS as its effect, mirroring the original relationship.

❌ Option B presents a professional and their charge, not a cause-effect relationship.

❌ Option C describes a treatment (antibiotic) and the microorganism it targets (bacteria), which is not a direct cause-effect in the same way as the original pair.

❌ Option D provides two words that are largely synonymous, describing a state rather than a causal link.

✅ The original analogy `PRACTICE : MASTERY` demonstrates a cause-and-effect relationship where consistent action (practice) leads to a desired outcome or skill (mastery).

Option A, `EFFORT : REWARD`, similarly shows that consistent action or input (effort) leads to a positive outcome or benefit (reward).

❌ Option B, `HUNGER : FOOD`, represents a need-and-satisfaction relationship, not a direct cause-and-effect where the first term causes the second.

❌ Option C, `BOOK : PAGE`, illustrates a whole-to-part relationship, as pages are components of a book.

❌ Option D, `SLEEP : DREAM`, describes an activity that occurs during a state, but sleep does not directly cause a specific dream, nor is dreaming the primary desired outcome of sleep in the same way mastery is for practice.

✅ The analogy `Heat : Expansion` establishes a clear cause-and-effect relationship where heat is the direct cause, and expansion is its resulting effect. Heat causes objects to expand.

❌ Option A, `Cold : Contraction`, perfectly mirrors this relationship, as cold is the direct cause that results in contraction.

❌ Option B, `Light : Shadow`, is a cause-and-effect relationship, but it describes the blocking of light to create an absence of light (a shadow), which is a different type of physical interaction compared to a direct material transformation like expansion or contraction.

❌ Option C, `Water : Evaporation`, is incorrect because water is the substance that evaporates, but the cause of evaporation is typically heat or exposure to air, not water itself.

❌ Option D, `Effort : Reward`, presents a cause-and-effect scenario; however, it is a more abstract or consequential relationship rather than the direct physical and observable phenomenon presented in the original analogy.

✅ The primary relationship in the pair 'Exercise : Fitness' is a cause-and-effect relationship, where exercise is the action or cause that directly leads to the desired effect of fitness. We are looking for an option that demonstrates the same causal link, where the first element causes the second as a positive or logical outcome.

✅ 'Work : Promotion' perfectly fits this pattern, as performing work (the cause) can lead to a promotion (the desired effect or outcome).

❌ Option A, 'Read : Book', represents an action and its object; reading causes understanding or knowledge, not the book itself.

❌ Option B, 'Sleep : Dream', shows an activity and an associated occurrence, but sleep primarily causes rest and rejuvenation, not necessarily dreams as its primary, desired effect.

❌ Option D, 'Eat : Hunger', reverses the cause-effect relationship; hunger is the cause that prompts one to eat, while satiety or nourishment is the effect of eating.