Venting lower level laundry

[RehabJunkie]

Great forum, and I've found a lot of help on here. I've attached an image of an existing waste, and vent from the upper level. Note: the existing vent has ONLY vent connections until it goes through the roof. The PVC in the image is all 3". If a laundry drain connection is added to the stack near the floor; can the laundry vent be plumbed into point (A), or point (B) ? Side/heel inlet to 90 degree?
Thanks,
Daniel

 

[Terry]

Legally, the washer vent would tie in at 42" above the next floor.