No one advised marking Asian alone. But one commenter weighed in with advice that could just as well have come from any college across the country: “You can put both. You can put one. You’re not dishonest either way. Just put how you feel.”

Until this year, questions about race on most college applications were much simpler. A student who was white with a distant American Indian ancestor , for instance, would most likely have identified himself as white.

But students can now choose from a menu of new boxes of racial and ethnic categories — because the Department of Education started requiring universities this past school year to comply with a broad federal edict to collect more information about race and ethnicity. The change has made it easier for students to claim a multiracial identity — highlighting those parts of their backgrounds they might want to bring to the fore and disregarding others, as Ms. Scott considered doing with her Asian heritage.

So the number of applicants who identify themselves as multiracial has mushroomed, adding another layer of anxiety, soul- (and family-tree-) searching and even gamesmanship to the process.

The new options have forced colleges to confront thorny questions, including how to account for various racial mixes in seeking diversity on campus. Is a student applying as black and Latino more desirable in terms of diversity than someone who is white and black? Or white and Vietnamese? Should the ethnicities of one’s distant relatives be considered fair game, or just parents? And what should be done about students who skip the race question altogether — a sizable number of whom, some studies have shown, are white, and do so either in protest or out of fear that identifying as merely white could hurt rather than help their chances in this new environment?