The correct answer is C. Selena started playing hockey, her favorite sport, when she was seven because her older sister was a star goalie.
Step-by-step explanation:
A sentence is punctuated correctly if commas, semicolons, and other punctuation marks are used according to grammar rules and conventions. In the case of the sentence presented, correct punctuation includes adding commas to enclosed "her favorite sport" because this section of the sentence is an appositive to describe "hockey", and according to grammar rules appositives are enclosed in commas as these are just extra information. Moreover, a period should be added at the end of the sentence to indicate the sentence or idea finished
According to this, the statement that is punctuated correctly is C. because this includes the commas to enclose the appositive as well as the period at the end of the sentence.