Los Angeles school district officials have allowed a group of high schools to choose from among six different laptop computers for their students — a marked contrast to last year’s decision to give every pupil an iPad. Contracts that will come under final review by the Board of Education on Tuesday would authorize the purchase of one of six devices for each of the 27 high schools at a cost not to exceed $40 million. In the fall, administrators, teachers and students at those schools will test the laptops to determine whether they should be used going forward. What they learn will affect the future of an ongoing effort to provide computers for all students in the nation’s second-largest school system. “The benefit of the new approach is clear,” said Los Angeles Unified school board member Monica Ratliff, who chaired a panel that reviewed the technology effort.