The answer is A because the dashes are placed in the correct places. The other options are close but not accurate.
The gerund phrase in the given sentence would be: Training show dogs. This gerund phrase is used as the direct object. The answer is option B. A gerund is a word that ends in -ing, but functions as a noun. A gerund phrase consists of the gerund plus other words that modifies.
I think it is A. Teenagers are an enjoyable and necessary part of our society.
