A compound adjective is formed when two or more adjectives are joined together to modify the same noun. These terms should be hyphenated to avoid confusion or ambiguity.
Option A: It is having two adjectives which define the age of the kid. The two adjectives are seven and year. So, this is the correct answer
Option B: Loves is the verb in this sentence
Option C: football is a noun in this sentence.
Option D: It is wrong as option A is correct
Option A is the correct answer.