Hi, I'm new to this forum so thanks in advance for the help! Our upstairs bathroom has dual sinks and one of them had a clogged drain. After several attempts to unclog it personally and through a plumber, I found out that the iron drain pipe in the wall was completely closed and thus needed to be replaced (50 years old, see photos A-1, and A-2). My question is this: Is there any benefit to re-plumbing the old iron pipes by using either option A or option B? Is one version better than the other? See photos. I've seen both options mentioned in this forum and not sure which to use. Is there a code concern? A sewer gas pressure concern? or anything else? Thanks for the help!