Robert: The school board is considering adopting a year-round academic schedule that eliminates the traditional three-month summer vacation. This schedule should be adopted, since teachers need to cover more new material during the school year than they do now. Samantha: The proposed schedule will not permit teachers to cover more new material. Even though the schedule eliminates summer vacation, it adds six new two-week breaks, so the total number of school days will be about the same as before. Which one of the following, if true, is a response Robert could make that would counter Samantha's argument? ['Teachers spend no more than a day of class time reviewing old material when students have been away from school for only a few weeks, but have to spend up to a month of class time reviewing after a three-month summer vacation.', 'Most parents who work outside the home find it difficult to arrange adequate supervision for their school-age children over the traditional three-month summer vacation.', 'In school districts that have adopted a year-round schedule that increases the number of school days per year, students show a deeper understanding and better retention of new material.', 'Students prefer taking a long vacation from school during the summer to taking more frequent but shorter vacations spread throughout the year.']