1. "Workers" and "tables" are both nouns, because they describe a group of people (workers) and a group of things (tables)
2. I may be right or wrong, but I believe "workers" is the subject in the sentence
This sentence is a complex sentence. Usually, a complex sentence is composed of one independent clause and one or more dependent clause. In the sentence, there is one independent clause (use the pump in the storage room) and one dependent clause (if the ball needs air). So, the answer is C.
Answer:
Hiking is a great FORM of exercise so option 4