The heirs of American conservationist and North Face Inc. founder Douglas Tompkins, who died in a 2015 South American kayaking accident, have chosen Lazard Ltd. to divest ranches in Argentina’s Mesopotamia region, two people aware of the plan said. MBA Lazard, the firm’s South America unit, is marketing ranches in Entre Rios province to high net-worth individuals, the people said, asking not to be named as the deal is private.