During your freshman year ninth grade, you take algebra 1 if you did not take it already.

where do the parenthesis belong in the sentence?

C) During your freshman year (ninth grade), you take Algebra 1 if you did not take it already.

C. During your freshman year (ninth grade), you take Algebra I if you did not take it already.

Explanation:

Parenthesis is the use of the round brackets in a sentence, most preferably to provide an explanation or afterthought for the statement just that has just been stated. This symbol is used to signify an added detail which need not necessarily be part of the sentence but needs to be.

In the given sentence, parenthesis has to be used for "ninth grade", which is also freshman year. Thus, the correct answer is the third option.