Rapid Action Battalion (RAB) members arrested four people, including a couple, in the capital yesterday for their alleged bid to sell a newborn, reports UNB.  Tipped off, a special team of RAB-3 conducted a raid on a flat in Shantibagh area around 5:30pm and rescued a two-day-old baby, who was supposed to be sold for Tk 1 lakh and arrested a couple -- Salma, 35, and her husband Saiful, 34, -- from the house.  RAB-3 officials said they conducted the raid after getting information from ambulance driver, Babu, 35, and one Anwara, 46, who were arrested by Rab members earlier.  One Bina Begum gave birth to the baby at a clinic in Badda on February 10.