For kids around the country, the District of Columbia offers a choice—if costly—array of educational opportunities. If you’re dissatisfied with your local school, for example, you can travel to D.C. and rub shoulders with future leaders at Maret ($12,100 a year) or St. Albans ($11,000). Slightly less—$10,800—enables you to sojourn with Chelsea at Sidwell Friends, while $5,900 will buy you…a year at a D.C. public high school. That’s the sum nonresident students in D.C. public schools will pay in the 1993-94 school year, according to figures proposed by the Board of Education. (Junior high and elementary school cost a bit less.) Unbelievably, such nonresident students do exist; according to spokeswoman Cheryl Johnson, the system boasted 180 of them last year. Who are these youngsters? According to Johnson, many are children of school employees who live in the suburbs but want their kids nearby during the day. Now that’s tough: not only paying to attend school in D.C., but also having to take Mom’s math class.