protecting vs to protect

[pinkprincess]

OG12-30

[question deleted by moderator]

Please explain why "to protect" can't be the answer.
Thanks~

[jlucero]

Per forum rules, please don't copy questions from paid resources, including Official Guides. If you have a specific question about a concept, feel free to post.

As for your question, take away the modifier in the sentence, and read what's left over. "to protect" is not a verb and without a conjugated verb, this sentence is wrong.