A compound adjective is formed when two or more adjectives are joined together to modify the same noun.
Option A: Over here "mouth-watering" is a compound adjective but it is not related to any time period or number.
Option B: "Four-week" vacation is a compound adjective with a number + time period.
Option C: "Wind-powered" is a compound adjective without any specified time period or number.
Option D: "World-Famous" is a compound adjective without any number and time period
Option B is the correct answer.