SINGAPORE – Alibaba Group Holding’s international online shopping unit is exploring a US initial public offering (IPO) as it weighs options to spur growth for the business that includes major e-commerce brands Lazada and AliExpress. The firm is in the early stages of consideration and the IPO’s size has yet to be determined, according to people familiar with the matter. The business group is in talks with banks that could potentially help prepare for the IPO next year, said one of the people. Alibaba’s US-listed shares rose 1.2 per cent in New York trading. The unit, which competes with rivals…