We decided to do all the task . . . . . . . . instead of waiting for help? A. of our own B. by ourselves C. ours D. all

The correct answer is: B. by ourselves

The sentence is about doing something without help. The answer must be a word or phrase that means “without help.”

• Of our own means “belonging to us.” This does not make sense in the context of the sentence.
• Ours is a possessive pronoun. This does not make sense in the context of the sentence.
• All is an adjective that means “the whole amount or number.” This does not make sense in the context of the sentence.

By ourselves means “without help.” This makes sense in the context of the sentence.