Answer: ninety.
Explanation:
Ok, let's work with numbers:
9 - nueve - nine
19 - diecinueve - nineteen
90 - noventa - ninety
And ninth is translated to "noveno"
So the sentence " La abuela de mi amiga tiene noventa años"
Would be translated to:
"the grandma of mi friend is ninety years old"
So the correct option is ninety
