Complete the analogy: BUTTER is to BREAD as

The relationship between butter and bread is that butter is a substance applied as a coating or layer onto the surface of bread. Similarly, paint is a substance applied as a coating or layer onto the surface of wood.

Step-by-step Derivation:
Step 1: Analyze the relationship in the base pair (BUTTER : BREAD). Butter is a spreadable substance used to cover or coat the surface of bread for enhancement or protection.
Step 2: Evaluate Option A (jam : jelly). Jam and jelly are both types of spreads; they are coordinates/synonyms, not a coating-to-surface relationship.
Step 3: Evaluate Option B (paint : wood). Paint is a substance applied to the surface of wood to coat it. This matches the 'coating : surface' relationship established in the base pair.
Step 4: Evaluate Option C (toast : jelly). Toast is a type of bread; jelly is a spread. The order is reversed (surface : coating) and the relationship is slightly different.
Step 5: Evaluate Option D (head : foot). These are anatomical opposites/extremities; no coating relationship exists.
Step 6: Evaluate Option E (yellow : blue). These are both primary colors; no coating relationship exists.
Step 7: Conclusion: Option B is the only pair that maintains the functional relationship of 'substance applied to a surface'.