To turn to the right is it a phrase, independent clause, or subordinate clause

Which sentence should gail insert before sentence 13 to provide an additional detail that supports the main point of the paragraph? a. stanton and mott agreed on most issues, but disagreed on a few important points. b. stanton had a stern husband who did not approve of her feminist views, while mott s husband was very supportive. both women developed a dislike of curtains and removed all the draperies from their homes. d. partly due to poor long-distance communication, they were not able to act immediately on their plans.