'Wilt' is related to 'Droop' in the same way as 'Thrive' is related to '______'.

In the given analogy, "Wilt" is related to "Droop." Both terms are synonyms and describe a similar state where something, often a plant, is losing its strength or vigour, generally sagging or falling. To find the analogous relationship for "Thrive," we look for a word that describes a similar state of flourishing or prospering, as "Thrive" means to grow vigorously or to flourish. Options analysis:

1. Decline - This is the opposite of thriving.
2. Careful - This doesn't relate directly to growth or health.
3. Deteriorate - This again suggests a decrease in condition, opposite of thriving.
4. Flourish - This is synonymous with thriving, indicating vigorous growth or a prosperous condition.

Therefore, the correct answer is: 4. Flourish - It matches "Thrive" as "Droop" matches "Wilt", all indicating similar conditions or states.