Read the sentence. celebrities who to raise awareness of significant world issues are more likely to have long-lasting bonds with their fans. the underlined part of the sentence needs a comma because it is a restrictive clause. is correctly punctuated because it is a restrictive clause. needs a comma because it is a nonrestrictive clause. is correctly punctuated because it is a nonrestrictive clause.

The correct answer is B.  The sentence "Celebrities who help to raise awareness of significant world issues...", doesn't need a comma before "who", because it's the case of a Restrictive Clause, meaning that, of all the celebrities, the only ones that are more likely to have long-lasting bonds with their fans are those that help to raise awareness..."

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