Choose the appropriate option which explains how the compound adjective given here was formed:
World-famous
A. Noun+Adjective
B. Noun+Noun
C. Adjective+Noun
D. Adjective+Adjective

Hint: An adjective is a word that describes something.
E.g. A red car (red is an adjective because it describes the car.)
Though sometimes we use more than one adjective to describe something.
A compound adjective is an adjective that contains two or more words, e.g. “I live in an English-speaking country.”
English-speaking is an adjective (that is used to describe a country). We use a hyphen in order to connect the word English with speaking to show that it is one adjective.

Complete answer:
To choose the correct option first analyze all the provided options:
A. Noun + Adjective - A compound adjective formed with the help of a noun and an adjective.
Example: She is a world-famous singer.
‘World’ is a noun and ‘famous’ is an adjective and hence this option is correct.

B. Noun+Noun - A compound adjective formed with the help of two nouns.
Example: There is some leaking in the water tank.

C. Adjective + Noun - A compound adjective formed with the help of one adjective word and one noun. Example: It was a last-minute decision.

D. Adjective+Adjective - A compound adjective formed with the help of two adjective words.
Example: They have a dark-blue uniform.

Note: We can understand the correct use of the hyphen between the two words with the help of this example,
Can we say that “He is a world and famous singer.” No, it doesn't sound correct and hence, we need a hyphen to join the words world and famous:
He is a world-famous singer. (Correct)