SIOUX FALLS, S.D.—A 60-year-old South Dakota woman was granted parole Thursday after serving two months in prison for the 1981 death of her infant son—a loss she kept secret for decades. The South Dakota Board of Pardons and Paroles was closely divided as it weighed the parole request from Theresa Bentaas, who entered an Alford plea to a first-degree manslaughter charge in October. The plea means she maintained her innocence but admitted that evidence could persuade a judge or jury of her guilt. South Dakota Circuit Judge Bradley Zell sentenced Bentaas in December to 10 years in prison, but suspended nine years of her sentence and said she should serve only two months. She had been held in jail for 73 days before trial and was supposed to be released to community supervision in July. The eight-member board was initially deadlocked Thursday on motions to grant and deny her parole. …