Explanation:

The correct answer is option 'B': Smart.

- When we describe someone as "smart," we usually mean that they possess intelligence, wit, and the ability to think and reason quickly.
- In the context of the sentence, the phrase "Her new husband is very ________" indicates that we are looking for a word that describes the husband's intellectual capabilities or intelligence.
- Option 'A': High is incorrect because it does not relate to intelligence. It could refer to the husband's social status or physical height, but it does not convey any information about his intelligence.
- Option 'C': Urgent is incorrect as it relates to a sense of immediacy or the need for prompt action. It does not provide any information about the husband's intelligence.
- Option 'D': Relaxing is incorrect as it refers to a state of calmness or leisure. It does not describe the husband's intelligence either.

Therefore, the correct answer is option 'B': Smart.

Key Points:
- The husband is described as "very smart."
- Being smart implies possessing intelligence, wit, and the ability to think and reason quickly.
- This characteristic is likely seen as positive or desirable in a spouse.
- The word "very" emphasizes that the husband's intelligence is significant or exceptional.