=====Disclaimer=====
I am not the best at proportions and this was made in about 30 mins
Body Proportions - Torso
Arms
When you look at the arms of Fig A they seem awkwardly on the body it looks like ones bigger than the other and the right arm is sticking out of the the body.
The arms on Fig B look whole lot better. They are comfortably on the body and seem about the same size. Thats because the right arm is hidden behind his chest and his left arm is apart of his body not just pasted on.
Back
Normaly you would think that you can't see the back of the man, so you don't include a back. He looks like he is made of paper (unless your going for that look, its a bad thing). It feels like a weird shape to the body and make every thing else look pasted on.
Unless your looking at the man straight on, you'll see some form of a back, Fig B shows this with the arms being in front of where the back is show more depth and making thinks seem like one thing.
Clothes
The sweater on Fig A looks like the sweater is facing us but the body isn't, it looks strange.
Fig B on the other hand looks like it is following the body of the man.
Shading
I tried to shade Fig A but it looked awful it was so strange to shade it in with shadows so I just did very basic shading. On Fig B it was easy and simple, period.
I hope this help you with your question maybe it cleared up some other things too.
